Weeks after Aztec warriors drove Hernán Cortés and his men out of Tenochtitlan in the bloody retreat known as La Noche Triste, the empire's nobles elected Cuitláhuac, brother of the slain Moctezuma II, as the new Tlatoani. His reign proved tragically brief: smallpox, introduced by the Spanish and their allies, was already spreading through the capital and would kill him within months, clearing the way for the empire's final collapse.

Ignatius of Loyola, the Basque soldier turned mystic, died in Rome after founding the Society of Jesus in 1540. His order became a global engine of Catholic education, missionary work, and Counter-Reformation intellectual life, sending priests as far as Japan and Peru. Loyola's feast day, July 31, commemorates a man whose leg wound at the Siege of Pamplona redirected the course of Christian history.