Solomon’s Stables were in fact vaulted cellars built by Herod the Great to support his immense platform of the Temple Mount when he extended and refurbished the
Second Temple in the first century BC. The vast masonry underpinning raised the ground level at the southeast corner of the Temple Mount by 150 feet. There are thought to be four levels of vaulting, but only the topmost level is accessible, and at present this is closed to tourists. The Umayyads reused Herodian masonry to restore this topmost level in the late seventh and early eighth centuries, and later the Templars rebuilt the arches. In addition to offering structural support for the Temple Mount platform and later the al-Aqsa mosque built above this spot, the cellars may have served Herod’s Temple as storerooms. The Templars were probably the first to use them as stables, and there are still rings attached to many of the pillars which were used to tether their horses.
A tunnel runs from the southern retaining wall of the Temple Mount underneath Solomon’s Stables. At a distance of 100 feet the tunnel is blocked by pieces of stone and debris, and archaeologists have not been able to examine it further because of objections from the Muslim authorities. But from the way the tunnel was constructed, often using large blocks from the period of Herod’s Temple, archaeologists have concluded that it was built as a postern by the Templars. The entrance would have been somewhere on the surface of the Temple Mount, and its exit in the southern wall would have allowed the Templars to emerge and make sudden surprise attacks against their enemies.