Imamat literally means leadership. According to the Shiite doctrine, Imamat is a divine leadership for the political and religious affairs of the Islamic Ummah. It is a divine office, for the Imams, similar to the Prophets, are chosen by Allah.
The leadership of the Islamic Ummah after the Prophet of Islam is one of the most important and controversial issues in Islam. The biggest dispute amongst Muslims has been the dispute over the issue of Imamat. In the Shi’a doctrine, Imamat is one of the five fundamental principles of Islam. The Shiites hold that Allah instructed the Prophet of Islam (P) to appoint 12 Imams, beginning with Imam Ali and ending with Imam Mahdi, as his successors.
The Shiites believe the issue of Imamat, like that of the Prophets, is beyond the choice of people. They hold that an Imam is an infallible person appointed by an infallible Prophet to safeguard the mission of the Prophet. According to this doctrine, the Imam is undertaking all the roles of the prophets with the exception of receiving the Divine Message through revelation.