Today is the feast of the beheading of Saint John the Baptist, an event which is mentioned in a source other than the Gospels. Here is the Jewish historian Josephus who wrote circa 93-94 AD regarding the death of the Baptist in his Jewish Antiquities:
About this time Aretas, the king of Petra, and Herod the Tetrarch had a quarrel on account of the following. Herod the tetrarch had married the daughter of Aretas and had lived with her a great while; but once when he was on his way to Rome he lodged with his half-brother, also named Herod but who had a different mother, the high priest Simon’s daughter. There he fell in love with Herodias, this latter Herod’s wife, who was the daughter of their brother Aristobulus and the sister of Agrippa the Great. This man ventured to talk to her about a marriage between them; she accepted, and an agreement was made for her to come to him as soon as he should return from Rome, one condition of this marriage being that he should divorce Aretas’s daughter. So when he had made this agreement, he sailed to Rome; but when he had finished there and returned again, his wife, having discovered the agreement he had made with Herodias, and before he knew that she knew of the plan, asked him to send her to Machaerus, a place on the border between the territories of Aretas and Herod, without informing him of any of her intentions. Accordingly Herod sent her there, thinking his wife had not perceived anything. But she had sent messages a good while before to Machaerus, which had been under the control of her father, and so all things necessary for her escape were made ready for her by the general of Aretas’s army. By that means she soon came into Arabia, under the conduct of the several generals, who carried her from one to another successively; and soon she came to her father and told him of Herod’s intentions. Aretas made this the start of his enmity toward Herod. He also had a quarrel with him about their boundaries in the area of Gabalis. So they raised armies on both sides and prepared for war, sending their generals to fight instead of themselves. And when they had joined battle, all Herod’s army was destroyed by the treachery of some fugitives who, though they were of the tetrarchy of Philip and joined the army, betrayed him. So Herod wrote about these affairs to Emperor Tiberius, who was very angry at the attempt made by Aretas and wrote to Vitellius to make war upon him and either to take him alive, and bring him in chains, or to kill him, and send him his head. This was the command that Tiberius gave to the governor of Syria.
Now some of the Jews thought that the destruction of Herod’s army came from God, and that very justly, as a punishment of what he did against John, that was called the Baptist: for Herod slew him, who was a good man, and commanded the Jews to exercise virtue, both as to righteousness towards one another, and piety towards God, and so to come to baptism; for that the washing [with water] would be acceptable to him, if they made use of it, not in order to the putting away [or the remission] of some sins [only], but for the purification of the body; supposing still that the soul was thoroughly purified beforehand by righteousness. Now when [many] others came in crowds about him, for they were very greatly moved [or pleased] by hearing his words, Herod, who feared lest the great influence John had over the people might put it into his power and inclination to raise a rebellion, (for they seemed ready to do any thing he should advise,) thought it best, by putting him to death, to prevent any mischief he might cause, and not bring himself into difficulties, by sparing a man who might make him repent of it when it would be too late. Accordingly he was sent a prisoner, out of Herod’s suspicious temper, to Machaerus, the castle I before mentioned, and was there put to death. Now the Jews had an opinion that the destruction of this army was sent as a punishment upon Herod, and a mark of God’s displeasure to him.