John was imprisoned and executed by Herod for boldly preaching against his adulterous marriage. John spoke against Herod because he married his brother's wife, Herodias.
Herod imprisons John the Baptist
Herod imprisoned John for the sake of Herodias. She held a grudge against John, and wanted him put to death. But Herod protected John because he enjoyed listening to him, and because his subjects thought John the Baptist was a prophet.
Herod celebrated his birthday by hosting a banquet. During the feast, the daughter of Herodias danced before Herod and his guests. She so pleased Herod that he swore to give her anything she requested, up to half of his kingdom.
John the Baptist is beheaded
The young woman went to her mother for guidance in what she should request. Herodias told her to ask for the head of John the Baptist.
She asked for the head of John the Baptist on a platter. Herod was sorry when he heard this. But because of his oath, and because of his dinner guests, Herod ordered the beheading of John.
John's disciples report to Jesus
When John's disciples learned of his death, they took his body and laid it in a tomb. Then they went and told Jesus, who departed with his disciples to a deserted place.
The historian Josephus wrote that Herod imprisoned John in a fortress called Machaerus, which is east of the Dead Sea.