Zhang Fei, courtesy name Yide, was a military general serving under the warlord Liu Bei in the late Eastern Han dynasty and early Three Kingdoms period of China. Zhang Fei and Guan Yu, who were among the earliest to join Liu Bei, shared a brotherly relationship with their lord and accompanied him on most of his early exploits. Zhang Fei fought in various battles on Liu Bei's side, including the Red Cliffs campaign, takeover of Yi Province, and Hanzhong Campaign. He was assassinated by his subordinates in 221 after serving for only a few months in the state of Shu Han, which was founded by Liu Bei earlier that year.
Zhang Fei is one of the major characters in the 14th-century historical novel Romance of the Three Kingdoms, which dramatises and romanticises the events before and during the Three Kingdoms period. In the novel, Zhang Fei became sworn brothers with Liu Bei and Guan Yu in the fictional Oath of the Peach Garden at the start of the novel and remained faithful to their oath until his death.