John the Baptist was son of a married priest of the Old Covenant named St. Zachariah

John the Baptist was the son of a married priest of the Old Covenant named St. Zachariah. 

"Once when he was serving as priest in his division's turn before God, according to practice of priestly service, he was chosen by lot to enter the sanctuary of the Lord to burn incense" (Lk. 1:8-9).

Solemnity of the Birth of John the Baptist

(June 24)

Also, see: https://marriedpriesthood.blogspot.com/2020/06/st-zachariah-married-priest-of-old.html