(February 17, 1201 – June 25, 1274)
Astute, versatile and improvising, this prime genius was among the greatest intellectuals of the Islamic Golden Age. As a jack-of-all-trade and master-of-all, he worked in diverse fields of arts and sciences. Nasir al-Din al-Tusi is remembered today as the first person who demonstrated that Trigonometry is independent of Astronomy. His Treatise on the Quadrilateral unveiled Spherical Trigonometry in a manner neither seen nor contemplated before. Due to these, he is fondly referred to as the “Father of Trigonometry”. He developed his famous Tusi-Couple, which was a geometrical contrivance that effectively replaced the cumbersome Ptolemy-Equant. His planetary motions essays (plus his accurate calculations of equinoxes) were indispensable to Copernicus, who used them as basis for investigating the then unknown realms of astrophysics. His bioresearches showcased some of the earliest forages into genetics and taxonomy. He classified living organisms into plants, animals and humans. As an avid reader of Avicenna’s works, Tusi was inspired to follow in his footsteps. From mathematics to medicine, and chemistry to physics, his tireless researches ushered-in some of the knowhow which foreshadowed Renaissance and the centuries of discoveries that followed it. For an example, this statement: “A body of matter cannot disappear completely. It only changes its form, appearance, condition, composition, color and other properties and turns into a different complex or elementary matter”, which is attributed to Tusi, precedes the similar view of today’s Law of Conservation of Mass. Both the minor planet, 10269 Tusi, and the 60-kilometer lunar crater, Nasireddin, are named after him.