Yang Guifei
He was appointed by Emperor Xuanzong (following the suggestion of Xuanzong's favorite concubine Yang Guifei and with the agreement of Chancellor Li Linfu) to be Jiedushi (regional military commanders) of three garrisons in the north—Pinglu, Fanyang and Hedong. In effect, An was given control over the entire area north of the lower reaches of the Yellow River, including garrisons about 164,000 strong. He took advantage of various circumstances, such as popular discontent with an extravagant Tang court, the synchronous Sogdian-involved Abbasid Revolution against the Umayyad Dynasty, and eventually the absence of strong troops guarding the palace coupled with a string of natural disasters. An Lushan was very influential in the Tang court, his close relationship with Emperor Xuanzong led to him being adopted by the imperial concubine Yang Guifei. The positions of power of Yang clan members (the family of the preceding Sui dynasty into which the Tang emperor had married) were important in this situation, especially complicated by the position of Yang Guifei’s relative Yang Guozhong in the Tang governmental administration.