When Cao Cao later surrounded Lü Bu at Puyang, the influential Tian clan, who were initially on Lü's side, switched allegiance to Cao and allowed his forces to enter the city. Cao Cao set fire to the eastern gate as a sign that he had no intention of reversing course, thereupon he came under attack and was defeated. Some of Lü Bu's horsemen captured Cao Cao but were unaware of his identity. Cao Cao saw a man riding on a yellow horse and lied that the man was him, so Lü Bu's horsemen released him and chased the rider. Cao Cao then dashed through the burning eastern gate and escaped from Puyang.