there is opinion that "the search for variants in the partial versions extant before the Caliph Uthman's alleged recension in the 640s has not yielded any differences of great significance". The two most influential codices at this time are ʿAbdullah ibn Masʿud's and Ubayy ibn Kaʿb's. Al-Qurazi recounted seeing the mushafs used by Ibn Mas'ud, Ubayy, and Zaid b. Thabit and finding no differences between them. ʿAbdullah ibn Masʿud's codex The most influential of the allegedly varying codices was that of ʿAbdullah ibn Masʿud, an early convert who became a personal servant to Muhammad. It is reported that he learned around seventy suras directly from Muhammad, who appointed him as one of the first teachers of Quranic recitation. Later he was appointed to an administrative post in Kufa by the caliph ʿUmar, where he became a leading authority on the Quran and Sunnah. Some sources suggest that Ibn Masʿud refused to destroy his copy of the Quran or to stop teaching it when the ʿUthmanic codex was made official. There are two points on which Ibn Masʿud's version is alleged to differ from the ʿUthmanic text: the order of the suras and some variants in the readings. Muhammad Mustafa Al-A'zami lists three reports concerning the omission of three suras, (Al-Fatiha and Al-Mu'awwidhatayn, the two short suras with which the Quran ends (Suras 113 and 114)), he then states that "early scholars such as al-Nawawi and Ibn Hazm denounced these reports as lies fathered upon Ibn Mas'ud." Most of the other differences involve only altered vowels with the same consonantal text, which caused variations in recitation. Dr. Ramon Harvey notes that Ibn Masʿūd's reading continued in use, and was even taught as the dominant reading in Kufa for at least a century after his death, in a paper discussing how some of his distinctive readings continued to play a role in Hanafi fiqh. Ubay ibn Ka'b's codex The second most influential codex was that of Ubay ibn Ka'b, a Medinan Muslim who served as a secretary for Muhammad. It is believed that he may have been more prominent as a Quranic specialist than Ibn Masʿud during Muḥammad's lifetime. There are reports that he was responsible for memorizing certain important revelations on legal matters, which from time to time Muhammad asked him to recite. In a few hadiths, Ubay is seen in a variety of roles. For instance, the "sheets" of Ubay