**Shams al-Din al-Samarqandi**'s full name is Shams al-din Muhammad ibn Ashraf al-Husayni al-Samarqandi.

Nothing is known of al-Samarqandi's life except that he composed his most important works around 1276. He wrote works on theology, logic, philosophy, mathematics and astronomy which have proved important in their own right and also in giving information about the works of other scientists of his period.

Al-Samarqandi wrote a work *Risala fi adab al-bahth* which discussed the method of intellectual investigation of reasoning using dialogue. Such methods of enquiry were much used by the ancient Greeks. He also wrote *Synopsis of astronomy* and produced a star catalogue for the year 1276-77.

In mathematics al-Samarqandi is famous for a short work of only 20 pages which discusses 35 of Euclid's propositions. Although a short work, al-Samarqandi consulted widely the works of other Arab mathematicians before writing it. For example he refers to writings by al-Haytham, Omar Khayyam, al-Jawhari, Nasir al-Din al-Tusi, and al-Abhari.

Not only did al-Samarqandi consult the writings of many other mathematicians before writing his short work, in turn several later mathematicians read al-Samarqandi's 20 page work and referred to it in their own writings. For example Qadi Zada mentions al-Samarqandi's short work on Euclid's propositions.

**Article by:** *J J O'Connor* and *E F Robertson*