King Herod the Great (the Herod who ordered the slaughter of the baby boys around Bethlehem -- see Matthew 2:13-20) built many great buildings including a fortress inside this artificial hill. His tomb has only very recently been found on the side of this hill.
The fortress was a fantastic complex with a big water reservoir (doubled as swimming pool???) and a palace at the bottom of the hill. Herod the Great was a very decadent man and even tried to surpass the buildings of Rome with his works in and around Jerusalem.
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