The Islands of the Sun and the Moon in Bolivia’s Lake Titicaca were two of the most sacred locations in the Inca empire. A pan-Andean belief held that they marked the origin place of the Sun and the Moon, and pilgrims from across the Inca realm made ritual journeys to the sacred shrines there. In this book, Brian Bauer and Charles Stanish explore the extent to which this use of the islands as a pilgrimage center during Inca times was founded on and developed from earlier religious traditions of the Lake Titicaca region. Drawing on a systematic archaeological survey and test excavations in the islands, as well as data from historical texts and ethnography, the authors document a succession of complex polities in the islands from 2000 BC to the time of European contact in the 1530s AD. They uncover significant evidence of pre-Inca ritual use of the islands, which raises the compelling possibility that the religious significance of the islands is of great antiquity. The authors also use these data to address broader anthropological questions on the role of pilgrimage centers in the development of pre-modern states.