History: The current Mosque of Omar was built in its current shape by the Ayyubid Sultan Al-Afdal Ibn Salah ad-Din in 1193 to commemorate the prayer of the caliph Omar.
Importance: after the Siege of Jerusalem in 637 by the Rashidun army under the command of Abu Ubaidah Ibn al-Jarrah, Patriarch Sophronius refused to surrender except to the Caliph Omar (579-644) himself. Omar travelled to Jerusalem and accepted the surrender. He then visited the Church of the Resurrection (today better known as the Church of the Holy Sepulchre) where Sophronius invited him to pray in the church, but Omar declined so as not to set a precedent and thereby endanger the church's status as a Christian site. Instead, he prayed outside, on the steps east of the church, in a place where David was believed to have prayed. The first Mosque of Omar was later built at that site.
Location: The Ayyubid Mosque of Omar in Jerusalem is located opposite the southern courtyard of the Church of the Holy Sepulchre in the Muristan area of the Christian Quarter in the old city of Jerusalem.