Status Updates From Conquistador: Hernan Cortes...

The most accurate accounts, estimated by native chroniclers in the years directly following the conquest, suggest that more than 200,000 Aztecs fell during the siege of Tenochtitlán, as well as 30,000 Tlaxcalans. Even by the most conservative estimates, the battle for the Aztec empire ranks, in terms of human life, as the costliest single battle in history.