On Lunar New Year's day, 756 (5 February), An Lushan declared himself Emperor at Luoyang, establishing a new state of Yan, making Zhang Tongru and the surrendered Tang official Daxi Xun () his chancellors. He created An Qingxu the Prince of Jin and another son, An Qinghe (), the Prince of Zheng. Meanwhile, Yan Zhenqing's cousin Yan Gaoqing (), who initially submitted to An, rose against An at Changshan Commandery (常山, roughly modern Baoding, Hebei) but was quickly defeated and delivered to An in Luoyang; An executed him and sent An Qingxu to make an initial attack against Tong Pass, and Geshu Han repelled the attack.