People who form the chains of narration regarding the Quran are as follows. Umar ibn al Khattab Uthman bin Affan Ali ibn abi Talib Abu Musa al Ash'ari Ubay Ibn Ka'b Abdullah ibn Masood Zayd Ibn Thabit Abu Hurairah Abdullah Ibn Abbas Abu al-Darda Of those ten, the two most important people were Zayd ibn Thabit the personal scribe of Muhammad and Ubay ibn Ka'b who was the foremost authority on the Quran after Zaid. The Shia view of the Qur'an differs from the Sunni view, but the majority of both groups believe that the text is identical. While some Shia disputed the canonical validity of the Uthmanic codex, the Shia Imams always rejected the idea of alteration of Qur'an's text. Uthman ibn Affan and the canonization According to Islamic tradition, the process of canonization ended under the third caliph, Uthman ibn Affan (r. 23/644–35/655), about twenty years after the death of Muhammad in 650 CE, though date is not exact because it was not recorded by early Arab annalists. The Qur'anic canon is the form of the Quran as recited and written in which it is religiously binding for the Muslim community. This canonical corpus is closed and fixed in the sense that nothing in the Quran can be changed or modified. By the time of Uthman's caliphate, there was a perceived need for clarification of Qur'an reading. The Caliphate had grown considerably, expanding into Iraq, Syria, Egypt, and Iran, bringing into Islam's fold many new converts from various cultures with varying degrees of isolation. These converts spoke a variety of languages but were not well learned in Arabic, and so Uthman felt it was important to standardize the written text of the Quran into one specific Arabic dialect. Another reason for compiling the Quran was that many Muslims who had memorized the Quran in its entirety (huffaz) were dying, especially in battle. According to the dominant version narrated by Bukhari, the reason for the final collection of the Quran was a dispute between Muslim forces from Iraq and Syria over the correct way of reciting it during communal prayers while on an expedition to Armenia and Azerbaijan. It is believed that the general Hudhayfah ibn al-Yaman reported this problem to the caliph and asked him to establish a unified text. According to the history of al-Tabari, during the expedition there were 10,000 Kufan warriors, 6,000 in Azerbaijan and