The Aztec Empire was established in 1428 when the city-state of Tenochtitlan formed a Triple Alliance with Texcoco and Tlacopan. Under the leadership of Itzcoatl and his successors, the alliance conquered vast territories in central Mexico. The Aztecs rose from humble beginnings, having founded their capital city Tenochtitlan on an island in Lake Texcoco in 1325. The empire reached its height under Ahuitzotl and Moctezuma II before falling to Spanish conquistadors in 1521.