Conquistadors followed Columbus to the Americas, seizing gold and converting natives to Christianity while spreading disease. Cortes allied with conquered natives against the Aztecs in Mexico, capturing their leader Moctezuma. Pizarro similarly captured the Incan leader Atahulpa in Peru after he paid a ransom. The Spanish were able to defeat the Aztec and Incan empires through superior technology, help from discontented Indians, and disease that killed many natives.