Which factor was more important in pizarro's conquest of the incas

In 1530, Pizarro returned to Panama. In 1531, he sailed down to Peru, landing at Tumbes. He led his army up the Andes Mountains and on November 15, 1532, reached the Inca town of Cajamarca, where Atahuallpa was enjoying the hot springs in preparation for his march on Cuzco, the capital of his brother's kingdom.