Qutb al-Din al-Shirazi

Qutb al-Din Mahmud ibn Mas'ud al-Shirazi was born in 1236 CE in Shiraz, Iran, into a distinguished family of physicians and scholars. His father was a physician and a disciple of the great Sufi master Ibn Arabi, and Qutb al-Din began studying medicine under his father's guidance from childhood. After his father's death he continued medical training at the Muzaffariyya hospital in Shiraz for about ten years.

His most transformative intellectual experience came when he traveled to Maragha in northwestern Iran to study under the legendary polymath Nasir al-Din al-Tusi at the famous Maragha Observatory. There he mastered advanced mathematics, astronomy, and philosophy, and became one of al-Tusi's most distinguished students. He later studied under other leading scholars across the Islamic world, traveling widely in his quest for knowledge.

In optics, Qutb al-Din made a landmark contribution that remained unrecognized for centuries. He was the first scholar to give a correct qualitative explanation of the rainbow, identifying that it is caused by the refraction and internal reflection of sunlight inside spherical water droplets — a breakthrough also developed independently by his student Kamal al-Din al-Farisi. This explanation preceded Descartes' account by more than three centuries.

In astronomy, Qutb al-Din worked within the tradition of the Maragha school, which sought to resolve contradictions in Ptolemaic planetary models. He composed major commentaries and contributed to the development of non-Ptolemaic planetary models. He was also a skilled physician, philosopher, and Sufi, and his encyclopedic work Durrat al-Taj covered a vast range of sciences. He spent the final decades of his life in Tabriz and died there in 1311 CE, leaving behind a corpus that influenced Islamic and, indirectly, European science.