[gentle music] - Welcome to University Place Presents.

I'm Norman Gilliland.

If you could go back 900 or 1,000 years in time and walk through Jefferson County in southeastern Wisconsin, you would come across a thriving village of 500 or 600, with mixed cultures and trade routes connecting to far-flung places, a place that we know as Aztalan.

And the goal of archaeologists and anthropologists today is, in some way, to bring back Aztalan.

And that's what we're going to do during this conversation of University Place Presents.

My guest is Sissel Schroeder, a professor of anthropology and archaeology at the UW-Madison, and welcome to University Place Presents.

- Thank you so much, Norman; it's a pleasure to be here.

- I think a lot of us know about the site, Aztalan, as it is today near Lake Mills, Wisconsin.

But put it in context for us in terms of, as Aztalan was thriving, what else was going on?

- So it was really sort of a thriving place, mostly between AD 1100 and 1200 with, you know, a little bit on either side, at a time when there were complex societies that had emerged across the southeastern United States.

And so these were different.

They were almost like small political units, and Aztalan was one of them on the far hinterlands or far reaches of the distribution of these societies across the southeastern U.S.

Many of its ties were with a site called Cahokia in Illinois, across the river from St. Louis, and we see some really, you know, some key material similarities as well as evidence that some of the people who at least spent the early years of their lives, if not most of their lives in Cahokia, did come to Aztlan.

- Was Cahokia sort of the nexus of this geographical area?

- It wasn't so much the nexus as it was just the largest.

[chuckles] It emerged as the largest and one of the earliest of these societies, and it had far-flung connections that really developed to the north.

Early on, they had strong connections to the south.

Later, those connections really transitioned to the north, the west, the east, and then as Cahokia went into decline, all of those external connections to the north kind of shrank pretty rapidly.

- Who are the people we're talking about in Cahokia and Aztalan?

- So we don't know what they called themselves.

We do know that both communities were multiethnic, that there were people who had come from different places and joined together in the St. Louis area and here in Wisconsin to create these settlements, these cities, if you will, that were occupied, for Cahokia, by maybe as many as 15,000, 16,000.

And Aztalan was much smaller, on the order of perhaps 600 people living there.

But they were, you know, they were just really, people were more mobile than we think of them being today, and so I think as family members might settle in a new place called Cahokia, other family members might follow them.

We know about the multiethnic nature of these communities because of the different styles of artifacts that they made, in particular pottery, that were very distinctive to certain regions and then came into, you know, came with them into these new areas.

So at a place like Aztalan, one of the things that's really quite dominant about it is that it has local ceramics, a strong signature of local ceramics associated with the local Late Woodland people, but it also has a significant percentage, you know, maybe as many as a third of the ceramics are what we associate with the Mississippian archaeological cultural tradition that look very different from the local ceramics and are of a style, and in some cases, even out of the clays from Cahokia.

- So pretty clearly not just traded that way, but actually intermingled at Aztalan.

- Yes, they brought their ceramics with them.

They brought some stone tools with them as well.

So they came somewhat equipped with what they were used to.

And then we do see at Aztalan, that sort of hybrid material culture forms through the coalescence of these people with different material culture traditions.

- What kind of terrain are we talking about at Aztalan?

- So Aztalan is situated along the Crawfish River.

It's on the west bank of the Crawfish River.

It's a somewhat sloping landscape with mounds on the high parts of the landscape, and that have been reconstructed, and it just has this, you know, just beautiful view into the valley of the Crawfish River.

It's a different kind of landscape than we see at Cahokia, which is in the middle of a very broad, pretty flat floodplain.

And so early on, archaeologists thought that Aztalan's location was, you know, a thing of curiosity.

They wondered why it might have been placed in that particular location.

- What conclusions did we draw?

Obviously, they had to have water, and they were right on the Crawfish River.

- It also appears that there is a spring, or was a spring there, and water was a very powerful cosmological material for the people from Cahokia and perhaps for the people that were living there locally as well, and so that might have also been something that was attractive.

There's also, Cahokia was a really, it was a big place.

It was a place that people made pilgrimages to, and it's possible that some people from Wisconsin made a pilgrimage to Cahokia and then brought friends back with them to join them at the site.

Some people think that perhaps people from Cahokia were feeling disenchanted with their life at Cahokia and may have chosen to move north, looking for a better place to live, better place for their families.

- Some things never change.

- Correct.

[both laugh] - Here's another view we have of that region.

You can see the river and you can see the landscape, which they would've found so attractive some 1,000 years ago, and presumably hasn't changed a lot in those 1,000 years.

- Other than that the river has been...

They've built levees to help contain flood waters, and they've channelized some of the creeks that ran across the floodplain.

That has altered the landscape a little bit, but probably the biggest alterations that have happened to the landscape there were by people.

People in the past who built mounds, like the really massive Monks Mound, which is the largest earthwork constructed by humans north of Mexico, but also many other smaller mounds, and that was kind of a, it's kind of a hallmark or a signature of the central sites in these political units.

- As we look at the broad view of Aztalan, and you get closer to the ground, much closer, what do you find in terms of infrastructure?

- So we have, within the community, we find, you know, the mounds are very visible, but once you look below the surface of the ground, we find trash pits, pits that may have been used for storage or for other things, sometimes quite massive.

We also find house basins.

So some of the houses were semi-subterranean, which would've helped offer some additional insulation in the winter, but also a little bit more cooling in the summer.

- Were they pointed south, those houses?

- No, they weren't necessarily pointed south.

- Really?

- Some, they were pointed in different directions, and we haven't excavated a lot of them, but they may have even formed small clusters, like little household groups of houses.

And, you know, the houses were of different sizes, different shapes, different forms, but they were all made out of wood, wooden posts set into the ground, and then probably some thatching and clay on the exterior surface.

- Any kind of defensive fortifications at Aztalan?

- So there is a wall surrounding this city, and it was a pretty massive wall, one of the larger ones for the Mississippian world.

It's also the earliest of these Mississippian-style palisades, based on some dates on multiple palisaded sites.

So it appears to be heavily defended, but it is set into a valley, and so the wall comes up only so high and then the hill continues to rise outside the site, and so you didn't have to go very far outside the wall to be able to see into the site.

So some of it's defensive.

Those defensive abilities were probably not as well developed as we might think when we just look at the wall.

The other thing is that at the corner of every bastion, there are these bastions that sort of jut out from the wall at regular intervals, and part of that is a structural thing to help the curtain wall stand.

If it was all just one straight wall, it could collapse, but those bastions are thought to have held platforms on which there could be guards or people looking for individuals approaching.

And at the corner of many of these bastions are tiny gates, just big enough for a person to come through with like a comma wall on the inside, and then there is also one large gate that might bring many people in through a narrow corridor.

So there's two different kinds of gates in this wall that made it more permeable than it would look from a distance.

And this might have been something that was really well-known to the people living within the wall, or it may have, you know, they had easy ins and outs, ways in and out of the community, and people from outside who didn't know that would be more intimidated by the appearance.

- At what point do we find latter-day, which is to say European-origin archaeologists looking at Aztalan?

- So that starts in the 1800s, around 18, about 1830 I would say.

As Milwaukee has been settled, people in Milwaukee begin to explore this land that, you know, that is new to them, not new to the Native peoples in this area, and word gets out that there is a walled city some three days' journey from Milwaukee.

Today, it's, you know, it's gonna be maybe an hour [laughs] from Milwaukee, but at that time, it was quite an undertaking to get to the site.

And a man named Nathaniel Hyer undertook this journey and visited the site.

And while he was there, he made a sketch map of the site that focused on what were the visible landscape features, in particular, a wall.

The wood of the palisade had already decayed, but all of the mud that had been coating this wall to make it a solid wall had kind of collapsed down.

Some of it was sun-baked, and so there was this kind of high ridge that went around the entire community.

And it had little areas that jutted out, which matched with the bastions that were eventually excavated by archeologists.

He also mapped the locations of four mounds, one of which we now know is not a traditional mound in the sense of something that was built up over time.

It was a consequence of a small natural land form that then had earth added to it that was then excavated into, and then, you know, added onto and excavated into, so really pretty complex.

And as he was looking at one of the mounds, the mound that's at the southwest corner of the site, he was struck by how it had multiple tiers to it.

And he had been reading Baron Alexander von Humboldt's travels through Central and South America, which was probably like a bestseller of the age.

- Norman: Yeah, for sure.

- And he recollected that he had seen an engraving in that picture of a site called Cholula that had a stepped mound.

And based on the engraving, he couldn't know that that was a stone mound, and he knew he was looking at an earthen mound, but the appearance was so similar.

And in the book, he noticed a passage that von Humboldt referenced that Cholula was an Aztec site, and the Aztecs' ancestral home was considered to be someplace to the north.

And somehow or another, von Humboldt got the idea that it was north of the 42nd parallel.

- Which would mean Wisconsin.

- Which would mean Wisconsin, exactly.

And so, you know, imagine in the early 1830s, and this young man is absolutely certain he's found the ancestral home of the Aztec, and they call their ancestral home Aztalan, so he gave the site the name Aztalan.

- Kind of jumped to a conclusion.

- Jumped to a really big conclusion, but the name stuck.

And so, you know, it's just something that, it helped establish a myth that the site has a connection to Mexico.

We have no evidence after, you know, over a century and a half of excavation about that.

But his map drew even more attention to the site, and I think one of the other things too that's important to recognize about the site is that it wasn't wooded.

It didn't have much in the way of trees.

It was fairly open.

Because it had been an open space, some of it had been gardened, and so it was really, it just was, it stood out in terms of the landscape of oak savannas that we have in southern Wisconsin.

- Who owned the property, that it was so well-preserved?

- It was the residues of the ancient people who had lived there.

So what they had left behind meant that there was not a lot of vegetation.

There were some trees growing there, but it wasn't, you know, like a dense cluster of oak trees that were in the middle of this community.

And that was kind of a, you know, that made it somewhat attractive to the early settlers as well.

In the 1850s, Lapham, who is, you know, he was the state geologist of Wisconsin.

- Increase Lapham.

- Increase Lapham.

He was a trained surveyor, which Hyer was not, so Lapham came out and put his surveying skills to use and created a new map of the site that bears a lot of resemblance to the one that Hyer produced, but is more accurate in some respects in terms of the actual measurements, and he notes features that, like some depressions in the soil that Hyer didn't note.

And so his idea of what the site represented, it really sort of fixed this impression in people's minds of this city with some earthen mounds surrounded by a wall, but with additional walls on the interior.

And this image of the site, it's a timeless image.

It's one of, this is like a place that was just, people walked away from and left it the way it was.

And so the assumption was pretty clearly expressed in a painting that was commissioned by the director, or the anthropology director at the Milwaukee Public Museum who had done excavations at the site, where he really focused on excavating these walls.

And he created an image that shows multiple walls standing at the same time, dividing the city into different districts, almost, one of which is a residential district close to the river, and then a district that's a plaza that had no evidence of occupation, just an empty plaza for community rituals.

And then an area around the perimeter of the site that was considered to be where the elites lived, and that was where you would find the mounds.

They were kind of around the perimeter of the site.

And-- - Is that based on other sites, that concept of a plaza and sort of the class distinctions and specified use for these various sections of the town?

- Yeah, by the 1900s, enough of these Mississippian sites had been investigated, not with modern methods, but enough had been investigated to recognize a particular pattern of mounds, typically at least one platform mound, arranged around an open area considered to be a plaza, and then houses around that, kind of ringing the community.

And then sometimes, a wall around the exterior part of the community.

And Aztalan stands out a little bit different in that the mounds are almost tucked up against the walls, and the residential area was long thought to just be along the river.

We're starting to get an understanding that the interior use of the site was much more extensive than what is reflected in those early maps, or even a map that was developed by Lynne Goldstein from Michigan State that shows where all of the excavations had been undertaken at Aztalan over more than 100 years of time.

And when you look at that map, you can see that really, a lot of the walls were investigated, the mounds were investigated, and parts of the so-called, you know, the village area near the river.

But huge swaths of the site were not excavated, or if they were, it would be a long trench taken with a backhoe.

[Norman chuckles] And-- - Norman: A little heavy-handed.

- Sissel: A little heavy-handed, and you know, the chance of finding something in a narrow trench like that is kinda low.

And so they would, you know, they did that, they didn't see anything, so they just figured there really was this massive plaza on the interior of the site.

- I think we'll be getting to that plaza a little bit later in terms of more contemporary techniques of examining it.

But in the meantime, you and some of your colleagues have gotten quite close to the ground [both laugh] in examining Aztalan.

- That we have.

It has...

I started a project there in 2015, and one of the things that has happened in archaeology as a discipline over the last 20 to 30 years is that use of remote sensing, terrestrial remote sensing equipment, has become really essential to what we do as archaeologists, especially when we're working on a site as special as Aztalan, which is a national historic landmark.

And so we don't wanna make a big imprint with our efforts as archaeologists.

So we've used a couple of different magnetometer instruments, we've used ground-penetrating radar, and we've got a fairly full coverage survey, geophysical survey of the interior of the site now.

And that just has involved walking back and forth across the site at, you know, intervals of like, every six feet, every ten feet, so that gives you a really intimate sense of what the landscape is like.

- Norman: Without digging it up?

- Without digging it up, exactly.

- And what sorta things did you start to find that you couldn't have found before?

- Well, one thing that we noticed, which I think there'd been a sense of before, was that the central part of the site was really wet.

The soil was really mucky, wet.

We'd sometimes kind of sink into it a little bit.

And we also, there was an area where we would cross over a ridge, and once we looked at the, overlaid our geophysical data on a 1937 aerial photograph of the site, we realized that was the old fence line between two different fields, and so it gave us this remarkable sense of how much erosion has happened because of Anglo-American style farming at the site.

That a lot of soil has eroded off of that slope and settled down near the river and probably in the river as well.

- You also seem to have found, inevitably, what you'd call anomalies, like, we don't know what this thing is, but you have a better sense of it once you get into the more sophisticated search techniques.

- Right, these geophysical methods show areas where maybe the soil moisture is different or soil compaction is different, something is different.

We call them anomalies.

And what we wanna do is then identify some of those anomalies and excavate to kind of ground truth what sort of archaeological phenomenon is creating that particular signature.

And so based on the ground-penetrating radar work that we had done in 2015, we thought that we had an area that might have had a house.

And so we did an excavation with that anomaly, and we did indeed find a house, and then we found that it was on top of another house, and then we found that it was on top of another house, and that it was on top of another house.

- Prime real estate.

- So prime real estate, exactly.

And it turned out that this house was situated in what had traditionally been called the plaza.

- Ah, back to the plaza.

- So the back, the edge of the plaza, and house upon house upon house.

And so, it opened our eyes to think about how Aztalan had evolved through time, and that perhaps all of the walls were not standing at once, and that they represented a sequential growth of the community or perhaps a sequential shrinking of the community.

And so we see that as, I think it was probably initially a growth of the community, and as that happened, people moved into new real estate that was opened up without their, not, you know, thinking about it as this massive plaza in the middle.

- Why do you suppose though, that piece of real estate with all the houses on top of each other, obviously select spot, right up against the plaza; why?

- It's possible, and we see this at some other Mississippian sites, that the houses that are largest may be adjacent to the plaza.

That it is people who have more resources or come from a higher-ranked social group.

It's possible that the center of the site, we think, had this spring in it, and so this house may have been closer to those springs, and we certainly saw evidence from the earliest houses that they probably got waterlogged at times during when they were occupied, and that they would bring more soil in and then build the house again, but at a slightly higher elevation.

- This starts to sound familiar too.

- Yes, it does, doesn't it?

- There was no FEMA at the time.

[both laugh] But the effects were much the same, weren't they?

- Yeah, the issues we face with our communities in some respects haven't changed.

- So about the plaza.

- Mm-hmm.

- What did you find when you actually looked at the plaza?

- So in the magnetometer data, that turned out to be really interesting in that there was a sort of central area that was magnetically quiet.

It looks like it's a more uniform gray, whereas much of the magnetometer data is these white spots with a black halo around it or a black spot with a white halo around it.

And in the middle, there's this really magnetically quiet area.

And it was really tempting to think that, well, that's what represents the plaza.

But magnetic, really waterlogged soils or very wet soils do not reflect magnetism in the same way as less waterlogged soils, and so when we see this sort of magnetically quiet area in the center of the site, we don't know.

The excavations that we did of the house upon house upon house actually are situated within that magnetically quiet area.

So we know that there are archeological features within the magnetically quiet part of the site.

And so, you know, additional work with other instruments might give us some more information, or perhaps taking some targeted excavations within that magnetically quiet area.

- Magnetically quiet area, the plaza.

- Mm-hmm, maybe, maybe not.

[laughs] - Yeah, so maybe a plaza, maybe not?

- So there's another area of the site that is a bit up-slope that runs between the northwest mound and the southwest mound and extends a little bit out from there, and from the magnetometer data, it's really noisy.

There's a lot of stuff going on in that area, and, you know, some of it could be igneous boulders that were left behind by the glaciers, but we've done some excavations in there in that area.

We did some excavations in 1996 in that area that were, in a way, sort of ground truthing the magnetometer data before, like, decades before we had the magnetometer data.

And the attraction to that area was that there was a, whenever archaeologists travel between Madison and Milwaukee, they always stop at Aztalan, always stop there, climb to the top of the northwest pyramid, typically, and look out over the site.

And in the summer of, I think it was 1988, archaeologists had done that, and when they looked across the site, this was a serious drought year, they noticed these circles of green grass in a field of nothing but brown grass.

And they were kinda curious about what those might be.

- Norman: They do stand out, don't they?

- Sissel: They really do stand out, and they look like, you know, they look like an alien invasion in some respects.

- Norman: [chuckles] Yeah, our version of crop circles.

- So you know, it took a decade before, again, Lynne Goldstein mounted a project to go and take a pretty systematic look at this part of the site, and I had the privilege of working with her on that project.

And what we did was to just dig, have students work on excavation units that were lined up in a trench to cross-cut the slope, cut through the slope in the area where these anomalies had shown up.

And first of all, when we removed the topsoil, we were into glacial gravel immediately.

There was no, like, soil development, and that might be a product of all the years of erosion.

And then in that gravel, these dark stains, big circles the size of the green grass in the field of brown, showed up, and they were the tops of massive pits that had been excavated, you know, six feet or more through gravel, and they were, like, evenly spaced apart going down that slope.

- Norman: Okay.

- Yeah, so these would be something we would think of as public features, that they may have been public storage pits for corn, they might have been, or for other foodstuffs, that they might have been, Lynne Goldstein has suggested that they may have been part of the mortuary practices of the society here.

- But you had no trace of corn or mortuary-related relics in these huge pits.

- Maybe a little bit.

Some of 'em were lined with reed mats, so we found remnants of these mats, and that was usually done for pits that had food in them.

Some personal ornaments were found in them, some foodstuffs were found in them, and they appeared to have kind of filled in over time, perhaps initially filled in somewhat intentionally, but then soil sort of washed in over time and filled them in.

And so now, we look at the magnetometer data and we see these anomalies that are like the same size as these massive pits, and they are, like, across this land form.

And so it may have been that it was a very active plaza.

It was a plaza that was filled with public things that were visible to the public, that the public might be involved with related to food, to agricultural practices, so it creates a very different view of this community than the one we inherited from the early maps that were done in the 19th century.

- I'm guessing metal detectors wouldn't do you a lot of good.

- No.

The... [laughs] Metal detectors, they might be useful, but the reality is, on the magnetometer data, the strongest signals that we see come from the activities of archaeologists.

If you see a large white dot with a black dot in the middle of it, so with a big white halo around it, that's like something like a railroad spike that was used as a corner stake for an old excavation unit.

There are... Across the site, there are these remnants of pin flags that archaeologists might have put into things when they were doing an excavation, like, "Okay, we're gonna kind of mark out the perimeter of where we're working here."

So the signature of archaeologists is very, very well-evident in the magnetic data at the site, so if we were to take a little metal detector out there, we'd most likely find something left behind by an archaeologist.

- So somewhat ironically, the archaeologists themselves become the subject of archaeology.

- Yes, indeed.

And I think it's kind of shocking because, you know, we try to have a minimal impact on the sites today.

We try not to leave behind things that are, you know, gonna create problems for future archaeologists.

And it's because we've learned a lesson, [chuckles] I would say.

- So with this sophisticated technology that you have today, what can you still not get to?

What can't you determine?

- If there are features that aren't filled with charred material or charred burned rock or something like that that would create a magnetic signal, we may not see those.

If they were just filled with the sediment that was right around the structure or the pit-- - Norman: Blend in too well.

- They'll blend in too well.

We won't be able to see those through geophysical methods.

We would see them if we were to undertake an excavation.

So these methods have opened our eyes to a view of Aztalan as a community that had a lot of stuff going on in it, but it isn't the full picture.

It certainly dramatically changed what we thought about the site for many, many years, as, you know, having a small village area and giant plaza area.

There may be a plaza; it's not quite where we thought it was, but it was filled with activity.

And there may be things that we're missing that don't signal in that way.

And there also are some of those anomalies that could be glacial boulders, glacial erratics or something, so there are ways that we might be able to start to distinguish those from ones that are actual archaeological features by looking at the nanotesla signal rate that is returned by the object.

But it opens up, in some respects, more opportunities, more questions for us to investigate, even though it has really radically transformed what we know about the site.

- It seems that a really big question still hangs over all of this though, Sissel, and that is, why did everybody leave?

- That's a really fantastic question, Norman.

That's like a question that drives dissertation research and careers in archaeology.

And it was probably a number of different factors that came together at the same time that had an impact on the people who lived at Aztalan that made them maybe not wanna be there any longer.

We know from studies of lake bottom sediment cores from around the Midwest that there was a pretty broad, geographically broad, significant drought, multi-year, maybe even multidecadal drought that began probably right around AD 1200, which is, you know, we don't see a lot of evidence of people at Aztalan much after that time.

So that climate, that climatic situation may have been one factor.

That drought, along with a massive flood that happened at Cahokia around, you know, maybe AD 1190, 1200, roughly speaking, may have really challenged leadership at Cahokia, and Aztalan as a place with such strong connections to Cahokia, might have seen those connections wither, and that might have had an impact on the social and political situation at Aztalan at that time.

And there may have been, you know, there may have been conflicts that arose with other people that were moving into the area because of the drought that were being displaced from where they had been.

So there's a lot of different things that could factor into this, some of which are testable that we can, you know, we could really begin to get us a better image of what was going on.

- Norman: Drought would be one possibility, flood would be another possibility.

Climate change, freezes, any other perhaps cultural reasons why the abandonment?

- Yes, there probably were, and those are some of the most interesting to think about, also some of the most challenging to investigate.

If we, you know, think back to how Aztalan formed as a coalescence of people bringing different cultural traditions together, it's important to think back to, well, what were those traditions that they brought with them?

Because those differences, those different practices and behaviors could potentially form cleavage planes within the society down the line after a period of time.

So when we look at what Late Woodland societies were like, and this is a, you know, term that archaeologists use to describe these people because we don't know what they called themselves, we don't know their names.

They lived in small villages or sort of dispersed households across the landscape.

They gardened, so they were, you know, growing squash, corn, and then maybe some native domesticates.

They made pottery that was, you know, had a distinctive cord-marked appearance.

And the Late Woodland peoples were also building effigy mounds.

And so their social and political systems were more egalitarian.

There were...

Decisions were reached through consensus as opposed to, you know, being decreed by an individual, so that's a very-- - Really, we know that?

- We infer that from mortuary contexts, household contexts that show very little material differentiation among the people in Late Woodland societies.

And their communities were on the smaller side.

They were something that could be managed through consensus, whereas once you get a small city of 600 people or you know, even a large city like Cahokia with possibly 15,000-- - You need some kind of administration.

- Consensus politics doesn't work so much, and so you get the emergence or development of hierarchical differences that help mitigate or adjudicate disagreements that might arise, that help pull people together around a single unifying activity.

And so when we look at Mississippian societies, these were people living in cities, large numbers of people where disputes were likely going to arise and would require some kind of social engagement to help adjudicate those differences.

But also at a city of this size, people may have, they may have differences in the things that they do and contribute to society.

We may have the development, and we see this at Cahokia, of craft specialists, individuals who at least on a part-time basis are working on crafting specialized objects, oftentimes out of exotic raw materials like copper that might have come from northern Wisconsin, northern Michigan, or marine shell that came from the Gulf Coast.

So you start to see this kind of social differentiation, and different practices might characterize different kin groups within such a large community.

And so if you think about, you know, the types of activities that Mississippian people brought the community around, related to building large mounds for the most part, of different sizes, different shapes, and also probably building the big walls that were around the community.

So these were things that pulled people together, but at Cahokia, they're at a massive scale.

And so when you get people whose lives have been lived in that kind of environment, where there is somebody that tells them what to do, there are people who serve as leaders in different aspects of the social realm, and you know, some people may be leaders when it comes to craft production, some might be leaders in developing mounds.

How do you engineer a massive mound like Monks Mound?

I mean, it kind of defies modern engineering today.

But it was done, and it has stood, with some slumping, for, you know, over 1,000 years.

- Norman: Structure on top of Monks Mound?

- There were structures on top of Monks Mound, just as there were some structures on top of the mounds at Aztalan.

And on Monks Mound, the structure was massive because there were many more people who might be considered suitable for engaging in ritual in a structure on top of a mound there.

So it's a very different kind of society.

It's like somebody from New York City who finds themselves living in Lake Mills today.

You know, it's that kind of scale of difference.

It's a little jarring.

And you bring with you particular practices, and the people who already live there that we as archaeologists would call the Late Woodland people, you know, they had a different set of practices, and somehow, they were able to bring it together for at least several generations.

And yet we also see, we see evidence that they were bringing things together in the material culture at the site, but we also see evidence of the maintenance of the separate cultural traditions.

And so, you know, one way in which they came together appears to have been in the construction of the palisades.

Mound building was probably another thing that brought all people together in the community.

And we do find a type of ceramic at the site that is kind of a hybrid between the late Woodland type and the Mississippian type.

It's, the Late Woodland type, in addition to having that cord-roughened exterior, the clay was tempered with grit, ground-up rock, so kind of a coarse temper.

And then Mississippian ceramics were tempered with ground-up clamshell, and it allowed them to make thinner-walled vessels that had a lot of strength to them.

And so there's this difference, you know, these technological differences, and what we see is that the Late Woodland technology of working with grit temper and local clays was then used to make vessels that looked like the Mississippian vessels.

They had that smoothed exterior, similar kind of shape.

So it's a kind of a hybrid.

It's bringing together a local technology with the appearance of something that has come into the community.

- Do we see other places in the region, I mean, that have that kind of cultural overlap?

If you don't have to go too far west in Wisconsin to find effigy mounds.

- Sissel: Right.

- But you don't really have effigy mounds at Aztalan, but you do have this kind of mix of the two cultures.

- We see effigy mounds across the river, from across the Crawfish River from Aztalan, and they have not been well-studied.

And so we don't really know, like, when were they built?

How does that relate to the development of Aztalan?

Because we haven't really seen evidence of Mississippian kinds of things on the other side of the river.

It's possible there was a recognition that this was a different landscape and that they weren't supposed to come together.

But it's a, you know, it's a really pretty interesting situation of two societies coming together, seemingly being successful, but perhaps the Late Woodland people gave up some of their traditions in order to adopt things that Mississippian people were doing, and maybe over time, that just didn't feel right, especially, say a society is confronted with an ecological disaster.

Then, you know, you may be thinking, "Well, what have I done to contribute "to this ecological disaster?

"I abandoned these traditions that have been part "of our society for, you know, hundreds of years.

Is that a reason that that happened?"

- It almost sounds like Aztalan was kind of a border town between these two cultures.

- You know, it might have been, but we don't really see other Mississippian sites in southern Wisconsin.

There are some sites along the Mississippi River near Trempealeau, and they are earlier.

They appear to be occupied somewhat earlier than Aztalan, and they actually look like outposts of people from Aztalan who brought everything they might need with them, from Cahokia rather, that brought everything they might need with them up there, and then they settled in a place where they didn't interact with local people.

Local people, it was like a, you know, sort of an empty pocket at the time, and they really didn't interact with nearby people.

So it was an enclave, and then Aztalan appears as more like a border town that brings people together.

It's possible that as the Trempealeau area was abandoned, some of those Mississippian people came to Aztalan, but we also see evidence of materials brought from Cahokia at Aztalan.

- And those trade routes, you mentioned things from the Gulf Coast and things from the Upper Peninsula of Michigan, copper for that and, of course, the shells for the earlier.

How far did these trade routes seem to go that reached Aztalan?

- If we look at the full scope of Native American occupation as we understand it from archaeology, which is gonna go back over 14,000 years, we see that these trade routes kind of expand, shrink, expand, shrink over time, and their expansiveness is different from one place to another at different points in time.

Certainly, Cahokia drew in material from Wisconsin, from Arkansas, from Missouri, from Illinois, maybe even Indiana.

Yes, definitely Indiana, Michigan, so a lot of stuff came in.

It is...

The ceramics are probably the most easy thing for us to look at to see what might have left Cahokia, because we can analyze the clays and describe, figure out where they might have come from geologically, what that source might be for them.

At Aztalan, we don't see, with the exception of the ceramics from Cahokia, the other materials, sort of exotic materials, or thing, you know, pipestone that came from the Baraboo Hills is one.

There may be a small amount of marine shell that came up from the Gulf Coast, probably through Cahokia, that's at the site too, but otherwise, a lot of what's there is local.

It reflects the knowledge that the local Late Woodland people had about their environment.

- Back in this mystery of what happened to it all.

I would think it would be pretty clear if there were signs of warfare.

You would see something burned or evidence that the palisade had been knocked down at some point, but it seems to have been untouched.

- It doesn't look like that was a factor.

It appears that the wall was standing when people left and it just degraded over time, and the clay that had been adhered to the wall to make it a solid wall just kind of collapsed down and created those ridges that were seen by Hyer with wonderment and mapped by him and by Lapham.

There have been studies of the ancestral skeletal remains from the site, and some people looking at those have concluded that interpersonal conflict of the type you might see with warfare was evident at the site.

Some people have drawn a different conclusion and suggested that the damage seen on the bones might have been part of a cosmologically significant mortuary ritual involving the bones of the ancestors who bring so much power with them, and so that one's still kind of left out in the open.

I have colleagues who really favor the warfare scenario, but I also think about how that wall was permeable, had so many different little gates in it, that it doesn't seem like a really strategic construction.

And its situation on the landscape, where you don't have to go that far out of the site to be able to look over the wall, also doesn't seem like a real strategic, a strategic design to the wall.

- It sounds as if the builders of Aztalan for those centuries, about what, 300 years or so?

- 200, 250.

- Really weren't that concerned about defense.

- And they might not have needed to be, given that they were a coalescent community of local people who could have helped negotiate relationships with other people living in the area.

The other thing to remember about the wall at Aztalan is, right now, it looks like it was the first wall of that type built in the Mississippian world.

And so it may have been also something of an experiment.

You know, working on, "Well, you know, "if we needed a defensive wall, what would it look like?

"How would we build it?

"We don't feel like we need it, so we're gonna put a bunch of little gates in it."

So there may have been some experimentation going on with wall construction at Aztalan.

It's also, when we look at Mississippian societies, one thing that archaeologists have often... One way that they've often interpreted monumental construction is that it was a way of demonstrating power.

Power of elites to command labor to be able to make these constructions.

So mounds at Cahokia are usually seen as something that the community interacted, you know, they contributed labor.

But only a small number of people were allowed to actually go onto the mounds or enter the buildings that were on the mounds.

So the finished construction was an elite area, but everybody participated in the construction, and a wall might be the same kind of thing.

And then it might further communicate that this is a community that is different than everybody else who's around us.

So it could serve as a, you know, external communication as you approach it, that wow, this is a different kind of place.

- Any sense of how the land was used in the years between the occupation of Aztalan and the arrival of Europeans?

- It looks like not much happened at Aztalan, but further down the Crawfish River, once it's into the rock drainage, we do know that there's an archeological cultural tradition that we call Oneota that had a pretty strong presence down there, and also had a strong presence in the Lake Winnebago area and in the La Crosse area.

So the Oneota peoples made pottery that was tempered with shell.

They decorated it in different ways than Mississippian people did.

They lived in villages, but smaller villages than what you would-- You wouldn't see them living in a community necessarily as large as Aztalan.

So there's another kind of culture that may have emerged out of the coalescence of Mississippian and Late Woodland, or may reflect what was happening with Late Woodland cultures living outside of the Aztalan sphere.

- Well, Sissel Schroeder, thanks for sharing some of the mysteries of Aztalan and solving some, and leaving some big ones unsolved.

- Thank you very much, Norman.

- I'm Norman Gilliland.

I hope you'll join me next time around for University Place Presents.

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