[3] In 923, Li Cunxu declared himself emperor of a new Later Tang, and later that year, he destroyed archrival Later Liang and took its territory under his control.
[6] He remembered Yang Tan's past contributions, and brought him back into active service, as a commander of the Lulong cavalry and infantry, stationed at Waqiao Pass (瓦橋關, in modern Baoding, Hebei).
It was said that while Yang was illiterate, he was capable in speaking and administration, such that he developed a good reputation in his governance and earned Li Siyuan's respect.
)[3] Yang was later transferred to be the military governor of Yiwu Circuit (義武, headquartered in modern Baoding),[3] and was serving there as of 936.
Li Congke put Zhang Jingda in command of the army against Shi and made Yang his deputy.
Li Congke, believing resistance to be futile, committed suicide with his family, ending Later Tang and allowing Later Jin to take over its territory.
He commissioned Yang Guangyuan as the military governor of Xuanwu Circuit (宣武, headquartered at Daliang); he also gave Yang the honorary titles of acting Taiwei (太尉) and chancellor (同中書門下平章事, Tong Zhongshu Menxia Pingzhangshi), and put him in command of the imperial guards at Luoyang.
[11] Around the same time, Fan Yanguang the military governor of Tianxiong Circuit (天雄, headquartered in modern Handan, Hebei) rebelled against Shi's rule.
When Yang's army reached Hua Prefecture (滑州, in modern Anyang, Henan), there happened to be a disturbance there over one imperial general (Fu Yanrao (符彥饒)) killing another (Bai Fengjin (白奉進)) over disciplinary disputes.
At Sang's suggestion, he moved Yang to Heyang Circuit (河陽, headquartered in modern Jiaozuo, Henan) and also gave him the titles of defender of Luoyang and full Taiwei, effectively stripping him of the powerful Tianxiong army (which Shi then divided in three, giving the commands to Gao Xingzhou, Wang Tingyin (王廷胤), and Wang Zhou (王周)).
[11] He further continued to submit petitions to accuse Sang of ruling unfairly and letting the government compete with private merchants.
In 939, Shi thus felt compelled to remove Sang from his chancellor position and send him out to serve as the military governor of Zhangde Circuit (彰德, headquartered in modern Anyang, which was previously given to Wang Zhou).
Yang, however, was both envious of the wealth he had and concerned that, given their past adversarial relationship during the Guangjin campaign, that Fan might be up to no good.
Shi, wanting to weaken his authority, stated that several of his officers all had great accomplishments during the Guangjin campaign and should be rewarded, and then made the prefectural prefects (i.e., removed them from Yang's command structure).
He subsequently moved Yang to Pinglu Circuit (平盧, headquartered in modern Weifang, Shandong) and created him the Prince of Dongping.
Late in 943, there was an occasion when Jing ordered Yang Guangyuan to return 300 horses that Shi Jingtang had lent from the imperial guard corps to the Pinglu army.
Yang Chengzuo thus, claiming that his mother was ill, opened the city gates one night and fled to Qing.
Shi Chonggui, in order to try to comfort Yang, sent a close associate to Qing to gift him jade belts, imperial horses, gold, and silver, but also sent the imperial guard generals Guo Jin (郭謹) and Cai Xingyu (蔡行遇) to Pinglu's neighboring circuit Tianping Circuit (天平, headquartered in modern Tai'an, Shandong), apparently to defend against a potential attack from Yang, while Yang had the prefect of Zi Prefecture (淄州, in modern Zibo, Shandong) arrested and taken back to Qing.
This, however, only caused Yang to be more arrogant, and he secretly encouraged Emperor Taizong (who had changed his state's name from Khitan to Liao by that point) to attack Later Jin, citing, as the reason, that Shi Chonggui had turned away from the close tributary relationship Later Jin had with Liao.
Meanwhile, Shi Chonggui's uncle by marriage, Du Wei the military governor of Chengde Circuit (成德, headquartered in modern Shijiazhuang, Hebei) sent his staff member Cao Guangyi (曹光裔) to meet Yang, trying to persuade him that rebellion was a dangerous course.
The Liao forces quickly reached Tianxiong, and then planned to cross the Yellow River at Majia Ford (馬家口, in modern Liaocheng, Shandong).
Shi sent Li Shouzhen the military governor of Taining Circuit (泰寧, headquartered in modern Jining, Shandong), to attack Qing.
His sons were spared, and Shi in fact commissioned Yang Chengxun as the defender of Ru Prefecture (汝州, in modern Pingdingshan, Henan).