The term used for the head of the Islamic state in Sunni Islam is Caliph.

The term used for the head of the Islamic state in Shia Islam is Imam.

The primary function of the Caliph in Sunni Islam is to lead the Muslim community in prayer, enforce Islamic law, and defend the Islamic state.

The primary function of the Imam in Shia Islam is to lead the Muslim community in prayer, enforce Islamic law, and interpret Islamic law.

Abu Bakr was the first Caliph of Islam.

Ali ibn Abi Talib was the fourth and final Rashidun Caliph.

The Islamic empire that was established by the Umayyad dynasty was called the Umayyad Caliphate.

The Islamic empire that was established by the Abbasid dynasty was called the Abbasid Caliphate.

The Islamic empire that was established by the Ottoman dynasty was called the Ottoman Empire.

The Islamic empire that was established by the Mughal dynasty was called the Mughal Empire.

The Ottoman Empire collapsed in 1922.

The Mughal Empire collapsed in 1858.

The Khilafat was abolished in 1924.

The movement that aimed to re-establish the Khilafat was called the Khilafat Movement.

The leader of the Khilafat Movement was Abul Kalam Azad.