Which civilization was known for having conquered Chichen Itza around 1000 C.E.?

The Toltecs were identified as the civilization that conquered Chichen Itza around 1000 C.E. This is significant as the Toltec culture, which emerged in central Mexico, expanded its influence throughout Mesoamerica, including the Yucatán Peninsula where Chichen Itza is located. The Toltecs are often credited with cultural and architectural achievements, which later impacted subsequent civilizations in the region. Their conquest marked a shift in the area's political and cultural dynamics, influencing the Maya civilization that thrived in the region prior to the Toltec's rise.

The other civilizations, such as the Aztec, Olmec, and Maya, had distinct histories and interactions with Chichen Itza and the Yucatán area. While the Maya were the original builders of Chichen Itza and thrived there earlier, they were not responsible for its conquest around 1000 C.E. The Olmecs, known for their earlier achievements, had largely declined by that time and thus were not involved. The Aztecs emerged later and primarily interacted with the legacy of earlier cultures rather than directly conquering Chichen Itza. The specific role of the Toltecs in this context makes them the correct answer to the question.