The term "Vicar of Christ" (Latin: Vicarius Christi), a Christian concept referring to an earthly representative of Jesus, has undergone theological and institutional development over centuries. Initially used to describe bishops as Christ’s agents, it became central to Catholicism, especially in designating the Pope as Christ’s earthly representative.
Thinkers such as Martin Luther challenged this role, casting doubt on papal authority, while others, like those in The Catholic World, highlighted the Pope’s divine commission. The idea also emerged in caesaropapism, where Byzantine emperors were referred to as "Vicars of Christ." This theme illustrates changing understandings of spiritual leadership, ranging from local pastoral duties to the doctrine of papal infallibility, emphasizing its lasting importance in Christian ecclesiology.