the reliability of traditional Islamic sources and applied the historical-critical methods to the early Islamic period, including the veracity of the conventional account of Muhammad. A major source of difficulty in the quest for the historical Muhammad is the modern lack of knowledge about pre-Islamic Arabia. According to Harald Motzki, "On the one hand, it is not possible to write a historical biography of the Prophet without being accused of using the sources uncritically, while on the other hand, when using the sources critically, it is simply not possible to write such a biography." In 1952 French Arabist Régis Blachère, author of a critical biography of Muhammad that took "fully into account the skeptical conclusions" of Ignác Goldziher and Henri Lammens, i.e that Islamic hadith had been corrupted and could not be considered reliable sources of information, wrote We no longer have any sources that would allow us to write a detailed history of Muhammad with a rigorous and continuous chronology. To resign oneself to a partial or total ignorance is necessary, above all for everything that concerns the period prior to Muhammad's divine call [ca. 610 CE]. All a truly scientific biography can achieve is to lay out the successive problems engendered by this preapostolate period, sketch out the general background atmosphere in which Muhammad received his divine call, give in broad brush strokes the development of his apostleship at Mecca, try with a greater chance of success to put in order the known facts, and finally put back into the penumbra all that remains uncertain. To want to go further is to fall into hagiography or romanticization. Historian John Burton states In judging the content, the only resort of the scholar is to the yardstick of probability, and on this basis, it must be repeated, virtually nothing of use to the historian emerges from the sparse record of the early life of the founder of the latest of the great world religions ... so, however far back in the Muslim tradition one now attempts to reach, one simply cannot recover a scrap of information of real use in constructing the human history of Muhammad, beyond the bare fact that he once existed. Michael Cook laments that comparing Ibn Ishaq with the later commentator Al-Waqid — who based his writing on Ibn Ishaq but added much colorful but made-up detail — reveals how oral history can be contaminated by