al-Allama al-Hilli

Jamāl ad-Dīn al-Ḥasan ibn Yūsuf ibn ʿAli ibn al-Muṭahhar al-Ḥillī (Arabic: جمال الدين الحسن بن يوسف بن علي بن مطهّر الحلي; December 1250 – December 1325), known by the honorific title al-Allāmah al-Ḥillī (Arabic: العلامة الحلي, "The Sage of Hillah") was a Twelver Shi'a Muslim scholar, journalist, and theologian of Iraqi Arab descent, who is often described as one of the most influential Shi'a authorities of his time. He was an expert in Twelver theology, a pioneering mujtahid, and the first learner to be referred to by the title "Ayatollah".

According to Al-Hurr al-Amili, his works were enumerated as many as sixty-seven times in bibliographical records. He lived during the time of the Mongol Ilkhanate rule over Iraq and Iran, and significantly influenced the Ilkhan ruler Öljaitü, who converted to Shi'a Islam after 1310. Al-Ḥillī is considered one of the first scholars to have successfully promoted and institutionalized Shi'a Islam in Iran.