Grand Ayatollah Sayyid Ali al-Husayni al-Sistani is the leader of the Shi'a Marji'iya (religious hierarchy) in Najaf, Iraq, the highest Shia authority in the country. He is a Marji' al-Taqlid (source of emulation) and is responsible for Marji'iya affairs and the Hawza 'Ilmyyia (religious clergy school) in Najaf, where he teaches on the podium of Imam al-Khoei. He was born in 1930 in Mashad (Iran) and has been residing in Iraq since 1951. He was educated in the prestigious Shia schools of Qum and Najaf. Since the U.S. invasion of Iraq in 2003, he has played a major political role.