Muhsin al-Hakim
Mohammad Mehdi Shamseddine was born on 1936 in Najaf, Iraq. Allamah al-Shaykh Abdul Kareem Shamseddine was his father and studied at Najaf seminary. When Mohammad was 12 years old, his father returned to Lebanon but Muhammad Mahdi decided to stay and finish his religious studies. Grand Ayatollah Abul-Qassim Khoei and Sayed Muhsin al-Hakim were his teacher at Najaf seminary. During his remain in the Iraq, he cooperated with Musa al-Sadr, Muhammad Baqir al-Sadr, and Mohammed Baqir al-Hakim.