Uthman ibn Affan (c. 574 - 656) was the third caliph, and is regarded as one of "The Four Righteous Caliphs". He reigned as caliph from 644 until 656.
Uthman was born into the wealthy Umayyad clan of the Quraish tribe in Mecca, a few years after Muhammad. Unlike most of his kinsmen though, he was an early convert to Islam, and was well known for using his wealth to benefit charities. He was also married to two of Muhammad's daughters at separate times, earning him the nickname Dhun Nurayn or the "Posessor of Two Lights". During the life of Muhammad, he was also part of the first Muslim emigration to Abyssinia, and the later emigration from Mecca to Medina.
According to Islamic tradition, Uthman was one of the ten people for whom it was witnessed that they were destined for Paradise; one of the six with whom Muhammad was pleased when he died. Uthman was also one of the first men to memorize the Qur'an and he would be instrumental to its compilation after the death of Muhammad.
Uthman would become caliph after the assassination of Omar in 644. Prior to his death, Omar appointed a group of six men to choose his successor from among themselves. Included in this group were Uthman and Ali. The committee chose Uthman.
He reigned for 12 years, and during his rule, all of Iran, most of North Africa, the Caucuses and Cyprus were added to the Islamic empire. In order to strengthen his control over the empire, Uthman appointed many of his kinsmen to governor positions, including Muawiyah I. This caused many problems though, and many people were angered by Uthmans preferential treatment of his own kinsmen. This matter was not helped by the fact that some of the misrule by some of the governors he appointed, and was worsened by the involvement of some Umayyads in a plot to kill the son of Abu Bakr.
Perhaps the one action which caused the most controversy for Uthman during his reign, however, was his attempt to develop a definitive text of the Qur'an at the expense of all others. His aim was simply to establish one true text of the revelation, in order for all Muslims to know what the Qur'an consisted of, what order it should be in, and how it should be written. Despite the controversy, Uthman was able to complete this task, which has since been recognised as a significant achievement in Islamic history. It reduced the number and frequency of disagreements over dogma, but many devout believers at the time accused Uthman of tampering with the sacred book.
These disagreements grew so large that parties from Egypt and Iraq would convene in Medina to address their grievances to Uthman directly. Eventually, the parties grew impatient with Uthman and laid siege to his house for more than 20 days in 656. Despite the crowds outside his home, Uthman refused help from his old friends, and the siege ended when some members broke into the house, and assassinated Uthman, while reading the Qur'an, and his wife, and threw his body on a dung heap where it languished for three days. He was eventually buried in Medina.