PHOTOGRAPHER'S JOURNAL, "Cuzco, part 8": Cuzco sits at 11,000 feet in a highland plain surrounded by mountains. If one controls the mountains, one can control all access to the plain and the city. Manco's siege caught the Spanish divided with Francisco Pizarro and half the forces far away in Lima establishing a new city. Pizarro's brothers were in charge in Cuzco with diminished forces. Saqsayhuayman was not only important because of its proximity to the city, but because prevented the Spaniards in Cuzco from slipping a messenger through to Lima to call for reinforcements.
The Incas might control Cuzco today if it hadn't been their custom when sunset came to stop fighting. The year was 1536. Machiavelli had been dead just nine years in Europe.