For the sake of Herodias (dia Hhrwidiada). The death of John had taken place some time before. The Greek aorists here (edhsen, apeqeto) are not used for past perfects. The Greek aorist simply narrates the event without drawing distinctions in past time. This Herodias was the unlawful wife of Herod Antipas. She was herself a descendant of Herod the Great and had married Herod Philip of Rome, not Philip the Tetrarch. She had divorced him in order to marry Herod Antipas after he had divorced his wife, the daughter of Aretas King of Arabia. It was a nasty mess equal to any of our modern divorces. Her first husband was still alive and marriage with a sister-in-law was forbidden to Jews ( Leviticus 18:16 ). Because of her Herod Antipas had put John in the prison at Machaerus. The bare fact has been mentioned in Matthew 4:12 without the name of the place. See Matthew 11:2 also for the discouragement of John en twi desmwthriwi (place of bondage), here en th pulakh (the guard-house). Josephus (Ant. xviii. 5.2) tells us that Machaerus is the name of the prison. On a high hill an impregnable fortress had been built. Tristram (Land of Moab) says that there are now remains of "two dungeons, one of them deep and its sides scarcely broken in" with "small holes still visible in the masonry where staples of wood and iron had once been fixed. One of these must surely have been the prison-house of John the Baptist." "On this high ridge Herod the Great built an extensive and beautiful palace" (Broadus). "The windows commanded a wide and grand prospect, including the Dead Sea, the course of the Jordan, and Jerusalem" (Edersheim, Life and Times of Jesus).