Banu al-Sabbah

Muhammad, Ibrahim and al-Hasan, the sons of al-Sabbah, were all among the skilled astronomers in the sciences of the heavens and of judgements. ²

They have a book, "The Proof of the Astrolabe Craft", which Muhammad wrote without finishing, and which Ibrahim completed. ²

There is also a book, "Making the Meridian by a Single Geometric Measurement", which Muhammad made and al-Hasan completed. Muhammad also wrote a treatise on the craft of marble inlay. ²