Uthman ibn Affan was the third and longest-reigned Rashidun caliph ruling from 644 until his assassination in 656. He was also a second cousin, son-in-law, and senior companion of the Islamic prophet Muhammad, and played a major role in early Islamic history. He is most famously known for the compilation and distribution of a standardized version of the Quran during his reign, known as the Uthmanic codex. This standardization established a uniform written text of the Quran, and the Uthmanic codex forms the basis of the Quran used by Muslims today.