1201-1274

Arab Mathematician and Astronomer

In 1259, Nasir al-Din al-Tusi persuaded the Mongol conqueror Hulagu Khan (c. 1217-1265) to establish an observatory at Maragheh in what is now Azerbaijan. The Maragheh observatory became a center of learning, producing information such as the tables contained in al-Tusi's Zij-i ilkhani. Al-Tusi was not merely concerned with mathematics in its applied form, however; in fact, he is often given credit as the first thinker to use pure trigonometry.

Al-Tusi, also known as Muhaqqiq-i Tusi, Kwaja-yi Tusi, and Khwaja Nasir, was born in the town of Tus in northeastern Iran. His father was a jurist in the Shi'ite Islamic sect, and al-Tusi received a strong religious education supplemented with teachings, provided by his uncle, in logic, physics, and mathematics. As a teenager he studied philosophy, medicine, and mathematics in the Persian city of Nishapur.

From at least the time...