Maunus/Wiki Commons

As far as tax collectors in colonial Mexico went, Gonzalo de Salazar, often dubbed "El Gordo," was a pinchpenny. The conquistador-turned-regional-chief demanded steep tributes from his charges living in an area called 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.