An Aztec codex prominently displaying maize, 1830.

Pre-Columbian Mesoamerican people groups (Aztecs, Mixtecs, and Mayans, e.g.) created codexes, textual records, that are one of the best primary sources for historical information about their cultures. This codex, Thirteen Cities Paying Tribute to Aztecs, was recreated in 1830 by Agostino Aglio. It reveals the importance of maize to the Aztecs. Maize, a corn that was first grown by indigenous people in Mexico nearly ten thousand years ago, is one of the most important crops to be “exchanged” in the Columbian Exchange. It can grow in nearly any climate; currently, under certain conditions, corn can produce a yield double that of wheat. After the Columbian Exchange, corn fed humans and livestock, contributing to population growth in many areas.