and he died several days later, though the exact circumstances of his death are unclear. The Spaniards and their allies attempted to retreat without detection in what is known as the "Sad Night" or La Noche Triste, realizing that they were vulnerable to the hostile Mexica in Tenochtitlan following Moctezuma's death. Spaniards and their Indigenous allies were discovered clandestinely retreating and were then forced to fight their way out of the city with heavy loss of life. Some Spaniards lost their lives by drowning, loaded down with gold. They retreated to Tlacopan (now Tacuba) and made their way to Tlaxcala where they recovered and prepared for the second, successful assault on Tenochtitlan. After this incident, a smallpox outbreak hit Tenochtitlan. The outbreak alone killed more than 50% of the region's population, including the emperor Cuitláhuac, as the indigenous of the New World had no previous exposure to smallpox. The new emperor Cuauhtémoc dealt with the smallpox outbreak, while Cortés raised an army of Tlaxcalans, Texcocans, Totonacs, and others discontent with Aztec rule. Cortés marched back to the Basin of Mexico with a combined army of up to 100,000 warriors. The overwhelming majority of warriors were indigenous rather than Spanish. Cortés captured various indigenous city-states or altepetl around the lake shore and surrounding mountains through numerous subsequent battles and skirmishes, including the other capitals of the Triple Alliance, Tlacopan and Texcoco. Texcoco, in fact, had already become firm allies of the Spaniards and the city-state and subsequently petitioned the Spanish crown for recognition of their services in the conquest similar to Tlaxcala. Cortés used boats constructed in Texcoco from parts salvaged from the scuttled ships to blockade and lay siege to Tenochtitlan for a period of several months. Eventually, the Spanish-led army assaulted the city both by boat and using the elevated causeways connecting it to the mainland. The attackers took heavy casualties, although the Aztecs were ultimately defeated. The city of Tenochtitlan was thoroughly destroyed in the process. Cuauhtémoc was captured as he attempted to flee the city. Cortés kept him prisoner and tortured him for a period of several years before finally executing him in 1525. Government The Aztec Empire was an example of an empire that ruled by indirect means. It was ethnically very diverse like most European empires but was more a system of tributes than a single unitary form of government unlike them. In the theoretical