Zayn al-Din Sayyed Isma‘il ibn Husayn Gorgani (c. 1040–1136), also spelled al-Jurjani, was a Persian 12th century royal Islamic physician from Gorgan, Iran. In addition to medical and pharmaceutical sciences, he was also an adept in theological, philosophic, and ethical sciences. Jurjani was a pupil of Ibn Abi Sadiq and Ahmad ibn Farrokh. He arrived at the court in the Persian province of Khwarazm in the year 1110 when he was already a septuagenarian. There he became a to the governor of the province, Khwarazm-Shah Qutb al-Din Muhammad I, who ruled from 1097 to 1127. It was to him that he dedicated his most comprehensive and influential work, the Persian-language compendium Zakhirah-i Khvarazm'Shahi.