Uthman ibn Affan was the third caliph of the Rashidun Caliphate, ruling from 644 until his assassination in 656. Uthman, a second cousin, son-in-law, and senior companion of the Islamic prophet Muhammad, played a major role in early Islamic history. During his reign as caliph, he was known for ordering the official compilation of the standardized version of the Quran, known as the Uthmanic codex, which is still used today.