Al-Aḥsāʾī, Shaykh Aḥmad b. Zayn al-Dīn b. Ibrāhīm (1166–1241/1753–1826), was a leading Imāmī scholar, philosopher and jurist; and originator of the influential Shaykhī school of Shiʿi Islam.

The chief sources on al-Aḥsāʾī’s life are a short treatise which he wrote for his older son, Muḥammad Taqī, dealing with the early years of his life; a work by his son, ʿAbd Allāh; and three sections of the Dalīl al-mutaḥayyirīn of al-Aḥsāʾī’s disciple and successor, Sayyid Kāẓim Rashtī.

Aḥmad al-Aḥsāʾī was born in the village of al-Muṭayrifī in …