Although long considered to be a barren region on the periphery of ancient Chinese civilization, the southwest massif was once the political heartland of numerous Bronze Age polities. Their distinctive material tradition--intricately cast bronze kettle drums and cowrie shell containers--has given archaeologists and historians a glimpse of the extraordinary wealth, artistry, and power exercised by highland leaders over the course of the first millennium BC. In the first century BC, Han imperial conquest reduced local power and began a process of cultural assimilation.

Instead of a clash...