Tlacopan was an important city in the ancient Mexica (Aztec) Empire, located in what is now Mexico. It was one of the three main city-states that formed the Triple Alliance alongside Tenochtitlan and Texcoco. Tlacopan played a significant role in the political and economic landscape of the region, contributing to the empire's expansion and wealth. The city was known for its strategic location and access to trade routes, which facilitated commerce and cultural exchange. Tlacopan's influence waned after the Spanish conquest in the early 16th century, leading to its decline and eventual integration into colonial Mexico.