Battle of Guandu
In 200, Yuan Tan accompanied his father at the Battle of Guandu against Cao Cao. Yuan Shao, however, was defeated in the conflict and fell sick shortly after returning to his base city of Ye. All along, Yuan Shao had intended to pass on his legacy to his youngest son Yuan Shang, who was favoured by Yuan Shao for his good looks, but the successorship had not been clearly established by the time Yuan Shao died in 202.