If ur asking why they changed: Despite their power and wealth the inca were overwhelmed by diseased and invasion by spanish conquistadors and their empire was taken in 1572.
How their empire developed and changed: At the time the incans had the largest empire in the world and when they started small, they began adapting many practices and policies of earlier cultures with begins development and prosperity. In 1438 Inka rulers began to conquer neighboring states which led to even more development in culture and government.