Jews believe this is location of an original Temple gate, possibly used for the ritual of the Red Heifer (Numbers 19:1-10). For Christians, Jesus entered here on Palm Sunday (John 12:13) and will enter again at the 2nd coming; Paul healed the cripple here (Acts 3:1-6). Muslims believe the Just will enter through this gate on Judgment Day - thus graveyard in proximity; left - Gate of Mercy, right-Gate of Repentance. Architecture suggests built ca. 685 as part of attempted Temple restoration by Umayyad caliph Abd al-Malik, though may be Byzantine; blocked off 8th c. Christians denied access to Haram. Crusaders opened it 2x year: Palm Sunday and Feast of the Exaltation of the Cross. Tradition holds Christian conqueror will enter through it, hence kept blocked.
