The Apostolic Fathers, also known as the Ante-Nicene Fathers, were core Christian theologians among the Church Fathers who lived in the 1st and 2nd centuries AD who are believed to have personally known some of the Twelve Apostles or to have been significantly influenced by them. Their writings, though widely circulated in early Christianity, were not included in the canon of the New Testament. Many of the writings derive from the same time period and geographical location as other works of early Christian literature which came to be part of the New Testament.

Christianity in the 1st century covers the formative history of Christianity from the start of the ministry of Jesus to the death of the last of the Twelve Apostles and is thus also known as the Apostolic Age. Early Christianity developed out of the eschatological ministry of Jesus. Subsequent to Jesus' death, his earliest followers formed an apocalyptic messianic Jewish sect during the late Second Temple period of the 1st century. Initially believing that Jesus' resurrection was the start of the end time, their beliefs soon changed in the expected Second Coming of Jesus and the start of God's Kingdom at a later point in time.