About 95 percent of Iraqis are Muslim and Islam is the officially recognized state religion. Islam came to the region with the victory of the Muslim armies under Caliph Umar over the Sassanians in A.D. 637 at the battle of Al Qadisiyah. The majority of inhabitants soon became Muslim, including the Kurds, although small communities of Christians and Jews remained intact in the area of present-day Iraq.