Emperor Zhaozong of Tang
Wang Sitong was born in 892, during the reign of Emperor Zhaozong of Tang. His father Wang Jingrou () was an officer of Lulong Circuit (盧龍, headquartered in modern Beijing), and his mother was a daughter of Liu Rengong, a late-Tang Dynasty warlord who would rule Lulong (although not yet at the time of Wang Sitong's birth — he would take over Lulong in 895, initially as a vassal of the major warlord Li Keyong the military governor ("Jiedushi") of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi), but later turning against Li and becoming an independent warlord).