Excerpts from Books and Wikipedia
"By autumn 637 the Arabs occupied all of Syria and Palestine except for Jerusalem and Caesarea. The fall of Jerusalem to the Arabs became inevitable. Sophronius's task was made easier by the Muslims' respect for Jerusalem as a holy city, but one of Sophronius's conditions was that he would surrender the city only to Umar in person. The terms offered by Umar were generous to the city's Christians, who were guaranteed protection on payment of jizya (tribute) to their Muslim overlords. Jews, however, were banned from Jerusalem. Most Christians in Palestine belonged to the Monophysite sect, which had been persecuted by the Byzantines, so they regarded the Arabs as liberators. Jerusalem remained under Muslim control until 1099." [1001 Days]