Zayd bin Thabit (Zayd ibn Thābit) was the personal scribe of the Islamic prophet Muhammad, serving as the chief recorder of the Quran text. He hailed from the ansar (helpers), but later joined the ranks of the Muslim army at age 19. After Muhammad's passing in 632, he was ordered to collect the Quran into a single volume from various written and oral sources. He was a noted expert on the Quran and spent much time reciting it. When Zayd was 1 years old his father died in the Battle of Bu'ath. Zayd was 11 years old when he asked permission to participate in the Battle of Badr. Since he was younger than 15 years old, Muhammad did not allow him to do so and sent him back. He then decided to try to win favour with Muhammad by learning the Quran. He was later appointed to write letters to non-Muslims and to collect and keep a record of the Qur'anic verses. Zayd was among those chosen by Muhammad to write down the verses of the Quran. He used to spend most of his time reciting the Quran and continued to learn the Quranic verses as they were recited by Muhammad. Zayd later volunteered to fight when he was 19 years old. This time he was accepted in the ranks of the Muslim army. Zayd's time to fight had come nine years after the establishment of the Muslim community in Medina. Zayd had the role of writing down the Quranic verses that Muslims believe were sent to Muhammad from Allah through the Angel Jibrail. After Muhammad's death, Zayd, who by this time had become an expert in the Quran, was assigned the role of authenticating and collecting the oral and textual Quranic revelation into a single bounded volume. This initiative was high on the Caliph Abu Bakr's agenda, especially after the Ridda wars, and the Battle of Yamamah in particular, in which 25 sahabis who had memorized the Quran were martyred. Umar convinced Abu Bakr that the Quran should be collected in one manuscript. During Abu Bakr's reign as caliph, he was given the task of collecting the Quranic verses from all over the Muslim communities.