The Anglo-Iraqi Treaty was signed due mostly to the strenuous efforts of the people of the former Ottoman provinces, a coalition of both Sunni and Shia Arabs. Major centres of insurgency during what was later called the "Great Iraqi Revolution" of 1920 included, Baghdad, Najaf, and Karbala. The insurgency effort in Karbala was inflamed by a "fatwa" issued by the grand mujtahid, Imam Shirazi. This "fatwa" made the observation that it was contrary to the principles of Islam for the region to be ruled by the British, who did not practice Islam. The "fatwa" ordered a jihad against the British forces of occupation.