What were the sources of strength and prosperity, and of problems, for the Incas?

Inca was the name of a ruling family that settled in the basin of Cuzco and formed the largest and last Andean empire. The empire, whose people we will call the Incas, was called Tawantinsuyu (TAH-want-een-soo-you), meaning “from the four parts, one,” expressing the idea of a unified people stretching in all directions.