Another date of extreme importance for purposes of reconstruction is that of the final surrender of Quauhtemoc The last Aztec emperor, who defended Tenochtitlan against the Spanish; his surrender marked the end of the Aztec Empire., the last of the Mexican rulers, which, according to the Mexicans, took place on the day 1 Serpent original: "1 Coatl", of the year 3 House original: "III Calli". Spanish chroniclers record the date as Aug. 13, 1521.

It was after noting the prominence of the combination-date, 1 Crocodile original: "Cipactli", 1 Reed original: "Acatl", in the newly discovered Codex, and the fact that it occurs eight times therein, that I verified how, in the Vienna Codex Also known as the Codex Vindobonensis Mexicanus I, a pre-Columbian Mixtec manuscript containing historical and genealogical records., the same date is repeated no less than twenty-one times, — a circumstance I had previously overlooked. The following complete list of the year-dates which occur in the Codex and Table III showing how often each year-date

TABLE II