Li Heng. This caused Emperor Xuanzong to favor An even more, but also later caused An to be apprehensive of whether Li Heng would bear continued resentment toward him over the incident. Later in 747, Li Linfu tried to use yet another case to undermine Li Heng. The general Wang Zhongsi, who was raised with Li Heng inside the palace on account of the fact that his father Wang Haibin () had died in battle in service to the empire, was accused of interfering with the campaign of another general, Dong Yan'guang (), against Tibetan Empire. Li Linfu broadened the accusation to an accusation that Wang was planning to start a coup to overthrow Emperor Xuanzong and replace him with Li Heng. At the intercession of another general, Geshu Han, however, Wang was spared from death, and Li Heng was not implicated. It was said that during this time period, Li Linfu made other attempts to undermine Li Heng, but with Gao Lishi and Zhang Shuo's son Zhang Ji (), who had married Li Heng's sister Princess Ningqing, protecting Li Heng, Li Heng escaped unharmed each time. As of 754, the chancellor in power was Yang Guozhong (Li Linfu having died in 752), the cousin of Emperor Xuanzong's then-favorite concubine Yang Guifei (unrelated to Li Heng's mother). Yang Guozhong and An were locked in a power struggle, and Yang repeatedly accused An of plotting a rebellion, but Emperor Xuanzong would not believe it, although Li Heng eventually came to agree with Yang Guozhong. In late 755, with Yang Guozhong repeatedly trying to provoke An into a rebellion, An finally did, from his base at Fanyang (范陽, in modern Beijing). After the rebellion started, Emperor Xuanzong briefly considered making Li Heng regent, but at the pleas of Consort Yang and her three sisters (who were fearful that Li Heng would act against them if he had regent powers), did not actually do so. By summer 756, An had declared a new state of Yan as its emperor, and his forces were approaching Chang'an. On July 14, 756, Emperor Xuanzong, with Yang Guozhong suggesting that they flee to Jiannan Circuit (劍南, headquartered in modern Chengdu), abandoned Chang'an and fled with Gao Lishi, Yang Guozhong, Wei, Li Heng, Consort Yang, and her family. The following day, July 15, the imperial guards accompanying the emperor, angry at Yang Guozhong, rose at Mawei Station (馬嵬,