St. John was born to Zechariah, a priest of the course of Abia, and Elizabeth, kinswoman of the Blessed Virgin Mary, in their old age — the angel Gabriel announcing his conception to Zechariah in the Temple at the hour of incense (Lk 1:5–25). Six months later Gabriel announced the conception of Christ to Mary; she went to visit Elizabeth, and at her greeting John leapt for joy in the womb — the first prophetic act of his life.
He grew up in the wilderness of Judea and emerged in the fifteenth year of Tiberius Caesar preaching baptism for the remission of sins and the imminent coming of one mightier than himself, the latchet of whose shoes he was not worthy to loose. Multitudes came out to him to be baptized in the Jordan. There he baptized Christ Himself and saw the Spirit descend as a dove.
His public ministry against the unlawful marriage of Herod Antipas to Herodias brought his arrest. Imprisoned at the fortress of Machaerus, he was beheaded at the request of Salome at a feast (Mk 6:14–29). Christ said of him: 'There hath not risen among them that are born of women a greater than John the Baptist' (Mt 11:11).
His head is venerated at San Silvestro in Capite at Rome, Amiens Cathedral, and the Umayyad Mosque at Damascus; his body, by tradition, at Sebaste in Samaria. He is the only saint other than the Blessed Virgin Mary whose birthday is observed liturgically as a solemnity.