Pachacuti reorganized the kingdom of Cusco into the Tahuantinsuyu, which consisted of a central government with the Inca at its head and four provincial governments with strong leaders: Chinchasuyu (NW), Antisuyu (NE), Kuntisuyu (SW) and Qullasuyu (SE). Pachacuti is thought to have built Machu Picchu, either as a family home or summer retreat, although it may have been an agricultural station.
Pachacuti sent spies to regions he wanted in his empire and they brought to him reports on political organization, military strength and wealth. He then sent messages to their leaders extolling the benefits of joining his empire, offering them presents of luxury goods such as high quality textiles and promising that they would be materially richer as his subjects.
Most accepted the rule of the Inca as a fait accompli and acquiesced peacefully. Refusal to accept Inca rule resulted in military conquest. Following conquest the local rulers were executed. The ruler’s children were brought to Cusco to learn about Inca administration systems, then return to rule their native lands. This allowed the Inca to indoctrinate them into the Inca nobility and, with luck, marry their daughters into families at various corners of the empire.
Source: Wikipedia
