Antonia

A square fortress on the east side of Jerusalem, north of the temple area, with which it had a covered communication. There was a tower at each corner, and it was isolated by high walls and trenches. It was rebuilt by Herod the Great, and named after Mark Antony. Josephus often speaks of it. It was "the castle" from which soldiers came down to rescue Paul from the Jews in the temple; and from its stairs he addressed the multitude, Ac 21:31-40.