1520, Cortes allies with Tlaxcala, enemies of the Aztec, assault on the empire begins. On the 1st of July, the Spanish forces were driven back. The Spanish and their native allies suffered heavy losses. (This is known as la Noche Triste - The Sad Night).
1520, Rule of Cuitahuac, tenth king of Tenochtitlán
1520, Cuitahuac dies from the first smallpox epidemic to hit the empire. Rule of Cuauhetemoc, eleventh and last king of the city.