The Spaniards arrived at Cajamarca with enormous advantages, both technological and biological. A devastating smallpox epidemic hit the Inca in advance of Pizarro's attack, not only killing thousands of Inca, but destabilizing them politically by contributing to a civil war. Smallpox had killed the previous Inca emperor and his heir, and Atahuallpa rose to power by defeating a rival claimant. The Spaniards also brought crucial information that Diamond argues the Inca had no way of knowing. Atahuallpa, without systems of writing or other sophisticated forms of recording information, assumed that he would simply be able to bribe Pizarro, who would then leave. He had no idea that the Spanish were actually bent on conquest and imperial aggrandization. Finally, the Spaniards had horses, steel weapons, and arquebuses, which gave them a major advantage over the Inca, who only had clubs and spears. Diamond will go on to explain that these differences, which so clearly favored the Spaniards, were the consequence of mostly geographical advantages enjoyed by Eurasian peoples.