Yuan Shao, the powerful warlord of northern China, had been decisively defeated at the Battle of Guandu by Cao Cao in 200. Two years later, he died, leaving his expansive territories of Ji province (冀州), Qing province (青州), Bing province, and You province to his three sons and a nephew: Yuan Tan, Yuan Xi, Yuan Shang, and Gao Gan. Although the eldest son was expected to succeed his father, Yuan Shang's supporters forged a document declaring the youngest son, him, as the successor. Yuan Tan, predictably resentful, rebelled against Yuan Shang after fending off Cao Cao's invasion together in 203. Yuan Tan had wanted to take the Yuan family headquarters of Ye, but Yuan Shang defeated the besiegers chased them three hundred kilometers away to Nanpi, the capital of Bohai commandery (渤海郡). The com