Al-Tusi, Nasir al-Din (1201-1274) was one of the greatest scholars of his time and one of the most influential figures in Islamic intellectual history. He was a scientist, mathematician, astronomer, philosopher, and theologian. He created ingenious mathematical models for use in astronomy.

Muhammad Ibn Muhammad Ibn al-Hasan al-Tusi, usually known as Nasir al-Din al-Tusi, was born in 1201, in Tus, in what is today called Iran. Under the instruction of his father, he studied the religious sciences and elements of the “intellectual sciences.” It is also thought that he studied logic, natural philosophy, and metaphysics with his uncle, as well as algebra and geometry with another person. He then moved to Nishapur (in what is now northwestern Iran), which at the time was a major center of learning, to complete his formal education.

Following the completion of his education, al-Tusi moved to an Isma'ili fort, which offered him protection from the Mongols who were invading the area around Tus. There he studied and wrote. He remained at various forts until 1256, when the Mongol Hulagu Khan ended the Isma'ili rule. Hulagu Khan, impressed with al-Tusi's abilities, appointed him his scientific adviser. Al-Tusi was instrumental in building an observatory in the new capital. Al-Tusi spent 12 years at the observatory and produced an accurate table of planetary movements. These tables remained popular among astronomers until the 1600's. In mathematics, al-Tusi pioneered spherical trigonometry and treated trigonometry as a new mathematical discipline. He developed six fundamental formulas for the solution of spherical right-angled triangles. He wrote on binomial coefficients, which Blaise Pascal later introduced.

Al-Tusi's influnence in other fields is evident in many of his writings. His work, Akhlaq-i-Nasri (The Nasirean Ethics), became his most well-know work in philosophy. It dealt with ethics and remained popular for centuries.

Al-Tusi was a productive writer. He wrote many formal books on a variety of subjects. He also wrote poetry. He died in 1274.