Beginning in the late 1400s, Spain built a vast American empire through conquest and colonization. Key events included Hernan Cortes' defeat of the Aztec Empire in Mexico in 1521 and Francisco Pizarro's conquest of the Inca Empire in Peru in the 1530s. Disease brought by Europeans devastated native populations. Spain imposed its culture and extracted wealth, particularly silver and gold, through the encomienda system which abused native laborers. By the mid-1500s Spain had established colonies across Latin America and parts of North America, becoming the richest and most powerful nation through its American territories.