Thursday, October 29, 2009

Why Build a City on a Mountain?

Why was the city of Calixtlahuaca (3 square km of occupation, probably 10,000+ inhabitants) built on a mountain? Most Mesoamerican cities built on mountains (think of Monte Alban or Xochicalco) were placed there for reasons of defense. Images of mountaintop cities in Mesoamerican codices (see my earlier blog entry on these) tend to show battles and defensive walls. But for several reasons, we don't think that defense was a major factor in the layout of Calixtlahuaca:
  1. We did not find any defensive walls or ditches.
  2. The largest civic buildings were not built in a protected location.
The second factor is quite striking. The royal palace was at the base of the hill, completley unprotected, as was a large unexcavated platform (a possible ballcourt). The two largest temples, structure 3 (circular temple, dedicated to Ehecatl) and structure 4 (rectangular temple, dedicated to Tlaloc) were built part-way up the hill, but closer to the base. Again, these were relatively unprotected. When defense is an issue, the main civic buildings are almost always built at the top of the mountain or hill (again, think Monte Alban or Xochicalco).

Well, what is so surprising about building a city on a mountain if defense was NOT a major consideration? The answer is the effort required to build the site. Every house that was built had to be accompanied by the construction (and constant maintenance) of stone terraces. Temples 3 and 4 required massive platforms and large excavations into the hillside to build level areas for these temples and their groups.

I have some hunches about why Calixtlahuaca may have been built on a mountain, but I will refrain from saying them now. One thing I am doing is looking for other ancient cities around the world whose residential zones were built on mountainsides, with the civic architecture at the base of the hill. Ephesis (the Roman occupation) is one example (see photo), and I am looking for others. If you have suggestions, let me know.


Geoff Carter said...

Not knowing this area and shooting from the hip, as structural archaeologist I would consider the following issues might be pertinent.
The nature of the ground on the plain.
Was it suitable for building?
If it is soft, it may not support stone foundations.

Is the agricultural land on the plain at a premium?
Was it important to preserve the flat fertile land for agriculture?

Where does the stone for the buildings come? How is it transported?
Building close to quarry may be a factor in an age without wheeled transport.

Other issues may be water supply and drainage

Michael E. Smith said...


Yes, those are relevant questions. Although I don't yet have definitive answers supported by good data, most of these factors would probably not have led to hillside construction (there was lots of level land available, it isn't marshy or soft). The one factor you mention that is probably relevant is the stone source. There is lots of stone on the mountain (Cerro Tenismo), and we located some quarries part way up. We could not date them well, however.

By the way, you have a great blog - I ran into it some time ago. We in the New World don't have much technical expertise in architecture of building, and we often come up with naive or partial models as a result.

Olin Tezcatlipoca said...

Sacredness of the site may be a motive for the location of Calixtlahuaca, as is the case for Tzintzuntzan, Guachimontones, Palenque, and other sites on hills or mountains. When you are there at those sites the sacred becomes more obvious. Sites like Teotihuacan have the caves,Cholula made the caves within its largest structure, Xochicalco has its cave, and the caves are all an issue of the sacred, as are mountains.

And of course even the fortified sites could have started as sacred sites then found need for protection as they grew in size and importance.

Olin Tezcatlipoca

Geoff Carter said...

I think the point that Olin makes is important in this context. Once you have powerful elites, people do things 'because they can'. There are still practical considerations, and in this case it is luckily it is mountains that are sacred not marshes!
The positioning of Akhenaten’s new Capital at Amama is as strange as the positioning of Las Vegas, and anyone who has seen the care traditionally taken in China with positioning of buildings, [Feng shui], will be aware that practical issues are not always the primary concern.
In China one of the ongoing concerns in architecture was mitigating the effects of earthquakes; could this be a concern for your builders?