Between the Yellow and Huai rivers, a conflict had erupted between Yuan Shu, Cao Cao, Tao Qian (Governor of Xu Province) and Lü Bu. Cao Cao forced the Yellow Turbans to surrender in 192, drove Yuan Shu to the south of the Huai River in 193, inflicted devastation upon Tao Qian in 194, received the surrender of Liu Bei (then a commander under Tao Qian) in 196, and captured and executed Lü Bu in 198. Cao was now in complete control of the southern part of the North China Plain.