The Mahdi Army was a Shia Iraqi militia founded by Muqtada al-Sadr in 2003 following the American invasion of Iraq. Its stated purpose was to resist the American occupation, protect Shiite areas, holy shrines, including the Imam Ali Shrine, and provide security and services. The Army became known for its fierce battles against coalition forces, most notably in Najaf, Sadr City, Basra, and Dhi Qar in 2004.