Who was the ruler of the Aztecs when Cortes and the conquistadors?

The ruler of the Aztecs when Hernán Cortés and the conquistadors arrived was Montezuma II. He reigned from 1502 until 1520 and was the ninth emperor of the Aztec Empire. Montezuma encountered Cortés in 1519, initially believing him to be a returning deity, which influenced his response to the Spanish invasion. His reign ended tragically as the conquest led to the fall of the Aztec Empire.