The sultanate was an institution of Islamic kingship, most particularly the dynasty of Ottoman rulers, who combined secular power with the religious leadership of the Sunni Muslim world by their claims to the Caliphate. The sultanate was abolished by the new Turkish republic on 1 November 1922, and the caliphate in 1924. These twin institutions were regarded by Shoghi Effendi as the 'arch-enemy' of the Baha'i Cause, (God Passes By, p. 407; and The World Order of Baha'u'llah, p. 173) and their collapse cited as an instance of Divine judgment.
The Caliphate was an Islamic institution established after the death of the Prophet Muhammad. The Caliph, the self-styled vicar of the Prophet of Islam, came to be regarded also as the "Commander of the Faithful," and the protector of the holy cities of Mecca and Medina. He became the leader of Sunni Muslims all over the world. By the 19th century, the title rested with the Ottoman rulers (Sultans). (Adapted from ‘A Concise Encyclopedia of the Baha’I Faith’, by Peter Smith; ‘God Passes by’, by Shoghi Effendi; and ‘The World Order of Baha'u'llah’, by Shoghi Effendi)