Montezuma II was the ninth ruler of Tenochtitlan, reigning from 1502-1520.  It was during his reign that the Spanish Conquest began.  It was during his reign that the Aztec Empire expanded to its largest size, through warfare.  There is much dispute about his actual personality, as most of what was written about him was written by the Spanish.  Everything that has been written about him shows him as a weak-willed and indecisive leader.  Some suspect that omens and Montezuma's superstitions were the ultimate downfall to the Aztec empire, as the arrival of the Spanish just happened to coincided with the "tying of years" ceremony at the end of a 52-year cycle in the Aztec calendar.  Montezuma died in 1520 after Cortes returned to help the Spaniards continue on with their battle against the Aztecs.  The accounts of what exactly happened to Montezuma are not quite clear, with there being several accounts as to how he died.