Chac II is a small site located about from the Great Palace, in the northwestern corner of the Sayil Valley. In the Terminal Classic, Chac II was a part of the greater Sayil urban area, however, Chac II predates the Terminal Classic occupation of Sayil with various dating methods (including radiocarbon, obsidian hydration, ceramic, and architectural dating) demonstrating that Chac II thrived in the Early to Middle Classic and participated in a trade network linked to the great metropolis of Teotihuacan in the distant Valley of Mexico. Chac II probably did not lose its dominance of the Sayil Valley until toward the end of the Late Classic and it is possible that Sayil was founded by the Chaac II elite, becoming a massive urban expansion of the earlier site.