Which Aztec emperor was ruling when Cortés arrived?

Moctezuma II was the Aztec emperor ruling when Hernán Cortés arrived in 1519. Also known as Motecuhzoma Xocoyotzin, he had ruled Tenochtitlan since 1502 and presided over the empire during its first sustained encounter with Spanish expeditions.

Cortés reached the Gulf Coast in April 1519 and advanced toward the Aztec capital with Spanish troops and Indigenous allies, including enemies of the Aztec Empire. On 8 November 1519, Cortés and Moctezuma met on the causeway leading into Tenochtitlan. Moctezuma received the newcomers and exchanged gifts, including valuable objects that intensified Spanish interest in the empire.

The encounter soon turned coercive. The Spaniards took Moctezuma hostage, and conflict spread through the capital. His death in 1520 remains disputed in its precise circumstances. He was followed briefly by Cuitláhuac and then by Cuauhtémoc, who led the final defense before Tenochtitlan fell in 1521. Moctezuma I had ruled much earlier, while Ahuitzotl reigned before Moctezuma II.