The term "Inca" refers to a royal family established in the Cusco region of the southern highlands of Peru. This family came to rule a pan-Andean empire that extended more than 4,000 km from Chile to the south of Colombia. The head of the royal family was the leader of the state. This large territory is believed to have comprised several different provinces under Inca control, with possibly ten million Inca subjects belonging to various ethnic groups. A common state language, the Quechua language, was imposed by the Incas to conduct political affairs and administrative business. People living in the Andes today, especially in the highlands of Peru, still speak Quechua.

The Inca empire was called Tahuantinsuyu, or "Land of the Four Quarters". The Incas believed that Viracocha, creator of the universe, had caused the sun to emerge from Lake Titicaca, which is located at the frontier between modern-day Peru and Bolivia. Inti, the god of the sun, modelled animals and humans in clay, and distinguished between the different ethnic groups. The Incas were chosen by Inti to be its representatives on earth. Thus, they were considered to be semi-gods, the children of the sun.

The Incas were originally organized as farming villages with war-like chiefs who harboured expansionist dreams. The birth and initial expansion of the Inca empire relied primarily on military force, but diplomacy also played an important role in the conquest of many regions. For example, many groups feared the strength of the Incas and were incorporated without major battle. The Inca state was well-organized and Inca rulers developed a national tax system, elaborate road and communication systems, and warehouse storage systems.The Incas ruled over most of the Andean region until AD 1532, the date of the arrival of the Spaniard Francisco Pizarro in Peru. The fall of the Inca empire was triggered by the Spaniards, their search for gold and the diseases they brought (mainly smallpox), but was aided by internal social conflicts and civil war raging between heirs to the throne