Big Four (Najaf)

The Big Four refers to the four contemporary leading Grand Ayatollahs of Twelver Shia Islam based in the holy city of Najaf in Iraq.

Background
All orthodox Twelver Shia Muslims follow the Islamic rulings of a Grand Ayatollah. Under Saddam Hussein, the clerics were oppressed. At present, the most prominent among them is Ali al-Sistani; who also serves as the head of the Najaf Seminary.