Gandhi felt that Hindu-Muslim co-operation was necessary for political progress against the British. He leveraged the Khilafat movement, wherein Sunni Muslims in India, their leaders such as the sultans of princely states in India and Ali brothers championed the Turkish Caliph as a solidarity symbol of Sunni Islamic community (ummah). They saw the Caliph as their means to support Islam and the Islamic law after the defeat of Ottoman Empire in World War I.[107][2][3] Gandhi's support to the Khilafat movement led to mixed results.