Sometimes chemistry can help researchers make sense of history. Scientists at the Field Museum in Chicago studied the materials in Peru’s historic pottery from the Wari empire and confirmed that it was produced at sites across different parts of the former empire, not in a central location.
Example of a ceramic drinking cup from the Wari site of Cerro Baúl, Moquegua, Peru that is similar … [+]
The Wari empire stretched along the coast of what is now Peru, between approximately the years 600 and 1000. Over the years, historians have been debating whether the Wari empire was centrally run or whether it was more of a distributed community with multiple centers. To learn about the historic civilization, researchers rely largely on archeological evidence and luckily there is a lot of that. The Wari created a lot of tools and art that hint at the way they lived. Among other things, archeologists have found well-preserved textiles, metal work and ceramics.
The ceramics in particular were of interest to the researchers at the Field Museum. Pottery is usually made with local clay, so if they studied the chemical composition of the clay, they would be able to tell if all the pots came from the same location or if they were made in different places.
“We’re trying to show that potters were influenced by the Wari, but this influence was blended with their own local cultural practices,” lead researcher M. Elizabeth Grávalos said in a statement to the Field Museum.
It wouldn’t be unusual or surprising if all the pottery did come from the same central location. For example, Ming porcelain largely came from a few central production sites, such as Jingdezhen. The ancient Romans also produced their pottery in Rome and shipped it across the empire from there. In a large civilisation like the Wari empire, it could be similar, with a central place producing most of the Wari pottery.
But that’s not what the chemical analysis showed.
To study the pottery, Grávalos and colleagues turned to lasers.
“We’d take a tiny piece of a pot and used a laser to cut an even tinier piece, basically extracting a piece of the ceramic’s clay paste,” Grávalos told the Field Museum. “Then helium gas carried it to the mass spectrometer, which measures the elements present in the clay paste.”
From the data they collected, the researchers learned that pieces of Wari pottery from different parts of the former empire contained different chemicals. That strongly suggested that they were made from local clay and that there wasn’t a central Wari porcelain production place. And they weren’t just copying instructions either.
“Even the Romans had local people doing things their own way,” noted the Field Museum’s Curator of Archaeological Science Patrick Ryan Williams, who oversaw the pottery study. “But what we’re finding in this study is the agency of local peoples and the importance of local economies. In some regions, we find that Wari colonists had their own production centers and were recreating Wari lifeways locally. In other areas, we see that local communities made Wari pottery in their own way. I think that’s what’s really important about this study.”
It means that the Wari empire likely wasn’t entirely centrally run, but that local communities had some agency in how things were done, at least when it came to pottery.
