In July 634 CE the Muslims won their first major battle over Byzantium. A year and a half later, in August 636, another major battle, fought near the Yarmuk River, won the Muslims their final control over both Palestine and Syria.

Arabic historiographic sources are inconsistent with regard to the date of the Muslim conquest of Jerusalem, which range between 636 and 638 CE. The Byzantine chronicler Theophanes supports the date of 638 for the conquest of Jerusalem by surmising that the city was under siege for two years. He relates that Sophronius, Patriarch of Jerusalem, died soon thereafter (March 638) in grief over the city's fate. According to traditional Muslim sources, the Muslim military commander Abu Ubayda b. Jarah had caliph `Umar Ibn Khattab receive the Christian city's submission in person. `Umar's entrance stunned the inhabitants of the city, as the caliph came mounted on a camel and in simple attire. `Umar's entourage was embarrassed at the sight of their commander's appearance before the Christian populace of the city. He obliged by conceding to mount a horse. According to Arabic tradition Umar remounted the camel explaining that riding a horse would be “to turn myself into another person altogether,… I fear that I will become too majestic in my own eyes, and the change would not be for the good”. According to Theophanes, the Patriarch Sophornius, on seeing `Umar, cried out: “Here is that appalling abomination, as prophesied by Daniel, standing on this holy site”. Theophanes continues that on his meeting with the Patriarch, `Umar was offered linen robes and shirts, but he agreed to wear them only while his own clothes were being laundered.

An agreement of surrender (aman), drawn up between `Umar and the inhabitants of Jerusalem, has been preserved in the writings of the great Arab chronicler of the earlier period, Tabari. It is possible that the original agreement was still in the hands of the Christian inhabitants of Jerusalem in the Middle Ages. According to the agreement, which was in letter form, the Christian populace of Jerusalem agreed to open the city gates for the Muslims, receiving the following in turn: security of life and property, protection of the churches and freedom of worship, prohibition of Jewish residence in Jerusalem; payment of a tax was obligatory and freedom was granted to choose between remaining in the city or departing from it.