Muslim historical writings first began to develop in the 7th century, with the reconstruction of the Prophet Muhammad's life in the centuries following his death. With numerous conflicting narratives regarding Muhammad and his companions from various sources, scholars had to verify which sources were more reliable. To evaluate these sources, they developed various methodologies, such as the "science of biography", "science of hadith" and "Isnad" (chain of transmission). They later applied these methodologies to other historical figures in the Islamic civilization. Famous historians in this tradition include Urwah (d. 712), Wahb ibn Munabbih (d. 728), Ibn Ishaq (d. 761), al-Waqidi (745–822), Ibn Hisham (d. 834), Muhammad al-Bukhari (810–870) and Ibn Hajar (1372–1449).