Wansbrough work stresses two points—that Muslim literature is late, dating more than a century and a half after the death of Muhammad, and that Islam is a complex phenomenon which must have taken many generations to fully develop.
[11] He postulated that Islam did not come into being as a new religion on its own but derived from conflicts of various Jewish-Christian sects[12] and from the need for a (fixed) sacred scripture upon which to base the Abbasid code of law: "The employment of scriptural Shawahid in halakhic controversy required a fixed and unambiguous text of revelation ... the result was the Quranic canon.
[13][14] The Quran was written and collected in a long process over 200 years and thus cannot be attributed to Muhammad, being more recent than traditional accounts date it.
[12] Thus, Wansbrough argued that the Quran "became a source for biography, exegesis, jurisprudence and grammar"[3][15] around the 2nd/3rd century AH in Abbasid Iraq (not the 1st-century Hijaz, Western Arabia, as traditionally dated and located).
Specifically Wansbrough thinks it must have been completed by Ibn Hisham around the time he composed his Sīra of Muhammad because of the "preponderance of Quran-based (historicised) narratives therein".
[14] Wansbrough thought evidence for the "seventh-century Hijaz" as the location of the Islam's origins was "[b]ereft of archaeological witness and hardly attested in pre-Islamic Arabic or external sources", but instead owed "its historiographical existence almost entirely to the creative endeavour of Muslim and Orientalist scholarhship".