During the Siege of Cuzco of 1536 by Manco Inca Yupanqui, a leader of the Sapa Inca, he took control of the city from the Spanish. Although the siege lasted 10 months, it was ultimately unsuccessful. Manco's forces were able to reclaim the city for only a few days. He eventually retreated to Vilcabamba, the capital of the newly established small Neo-Inca State. There his state survived another 36 years but he was never able to return to Cuzco. Throughout the conflict and years of the Spanish colonization of the Americas, many Incas died of smallpox epidemics, as they had no acquired immunity to a disease by then endemic among Europeans.