As far as tax collectors in colonial Mexico went, Gonzalo de Salazar, "El Gordo," was a pinchpenny. The conquistador-turned-regional-chief demanded steep tributes from Tepetlaoxtoc just north of what is now Mexico City. To expose El Gordo's greed, census takers from the Acolhua-Aztecs, a subset of the larger Aztec group, set out to count their own numbers in the mid-1500s and tally the extent of their farmland and hence their tax burden. They did a remarkably good job, a new study suggests. The early surveyors calculated the sizes of their farms with a degree of accuracy likely beyond the means of El Gordo or his cronies.
The Tepetlaoxtoc census, also known as the Codex Vergara, was much more than a simple survey. This record incorporated icons for every adult and child in the region, as well as detailed maps for at least 386 farms. The surveyors measured the borders around each of these fields and then calculated their areas in square tlalcuahuitls, units equal to roughly 2.5 meters.
Using these records, Clara Garza-Hume, a mathematician (National Autonomous University of Mexico, Mexico City) and colleagues went back to the codex to check the Aztecs' math.
What the team could do, however, was calculate the wiggle range of possible shapes for each of the fields. And the surveyors "did quite well" in matching those shapes, she says. The Aztecs calculated the sizes of their farms within a 10% error range about 85% of the times.
But the Aztecs could just have easily have fudged their measurements, trying to trick their governor out of a few spools of cloth. Luckily, a field near the modern town of Texcoco still vouches for their honesty; this sloping lot contains the remnants of 38 old farms censused in the codex. Using GPS markers, the 38 farms had once taken up about 135,577 square meters, not too far off from the Aztecs' estimate of 124,072 square meters.
The Codex Vergara did put the Spanish in their place, at least mathematically. Early colonialists were largely clueless when it came to land surveys, rarely knowing for sure where their expansive cattle ranches started or stopped, says geographer Andrew Sluyter (Louisiana State University, Baton Rouge.)
Studies like these are important because they show the Mesoamericans' prowess in fields outside of astronomy, says archaeologist Michael Smith (Arizona State University, Tempe.) Still, indigenous Mexicans didn't always use their record-keeping acumen for good, Smith adds. The Aztecs, conquerors themselves, would have needed meticulous notes to squeeze every penny out of their squashed foes.
Thanks to coldrum for the link to this article at news.sciencemag.org. See the article for more.
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