Antonia

a fortress in Jerusalem, at the north-west corner of the temple
area. It is called "the castle" (Acts 21:34, 37). From the
stairs of this castle Paul delivered his famous speech to the
multitude in the area below (Acts 22:1-21). It was originally a
place in which were kept the vestments of the high priest. Herod
fortified it, and called it Antonia in honour of his friend Mark
Antony. It was of great size, and commanded the temple. It was
built on a plateau of rock, separated on the north from the hill
Bezetha by a ditch about 30 feet deep and 165 feet wide.