Josephus, Antiquities XVIII.119. Josephus’s account is reinforced by later Christian authorities. Origen, writing c. 250 states: “For Josephus in the eighteenth book of the Jewish Antiquities bears witness to John as the one who was ‘the Baptist’ and who promised purification for those who were baptized” (Contra Celsum 1, 47).

In c. 324 Eusebius likewise confirms the validity of Josephus when he cites the relevant text: “John called the Baptist […] For Herod slew him […] On account of Herod’s suspicion John was sent in bonds to the above-mentioned citadel of Machaerus, and there slain” (Ecclesiastical History 1.11.4–6).

Eusebius was the first who clearly states that the description of Josephus does not contradict the Gospels, but rather is a confirmation of and “testimony” to them. His observation includes the following: “John the Baptist was beheaded by the younger Herod, as is stated in the Gospels. Josephus also records the same fact, making mention of Herodias by name, and stating that, although she was the wife of his brother, Herod made her his own wife after divorcing his former lawful wife […] The same Josephus confesses in this account that John the Baptist was an exceedingly righteous man, and thus agrees with the things written of him in the Gospels” (Ecclesiastical History 1.11.1 and 3).