a few hundred horsemen and with Dong Zhuo's head tied to his saddle, passed through Wu Pass and went to join Yuan Shu in Nanyang Commandery. The Sanguozhi and the Houhanshu give differing accounts of how Yuan Shu treated Lü Bu. The former claimed that Lü Bu expected to be received warmly because he felt that he had helped Yuan Shu take revenge by slaying Dong Zhuo. However, Yuan Shu detested Lü Bu because of his duplicity so he refused to accept him. The latter stated that Yuan Shu treated Lü Bu generously, but Lü behaved arrogantly as he felt that he deserved better treatment because he had done Yuan a favour by killing Dong Zhuo. Lü Bu also allowed his men to plunder the area. Yuan Shu became worried that Lü Bu would pose a threat to him, and Lü also felt uneasy after he heard that Yuan was suspicious of him, so he left. Joining Yuan Shao and Zhang Yang After leaving Yuan Shu, Lü Bu then headed to northern China to join Yuan Shu's relative, Yuan Shao. He assisted Yuan Shao in attacking Zhang Yan at Changshan. Zhang Yan had thousands of elite soldiers and cavalry. Lü Bu led his subordinates Cheng Lian (成廉) and Wei Yue (魏越) and dozens of riders to raid Zhang Yan's camp, killing several enemies and then fighting their way out. They did this three to four times every day continuously for a period of over ten days and eventually defeated Zhang Yan's forces. Lü Bu behaved arrogantly in front of Yuan Shao because he perceived that he had done the Yuans a favour by slaying Dong Zhuo. He belittled Yuan's followers and treated them with contempt. He once asked for more soldiers from Yuan Shao but was refused, after which he sent his men to plunder Yuan's territories. Yuan Shao was greatly displeased and felt that Lü Bu posed a threat to him. Lü Bu sensed that Yuan Shao was suspicious of him so he wanted to leave northern China and return to Luoyang. Yuan Shao pretended to agree and recommended Lü Bu to take up the appointment of Colonel-Director of Retainers (司隷校尉) while secretly plotting to kill him. On the day of Lü Bu's departure, Yuan Shao sent 30 armoured soldiers to escort him and personally saw him off. Along the journey, Lü Bu stopped and rested inside his tent.