Sahner, associate professor of Islamic history at Oxford University, makes innovative use of a familiar but usually ignored source of information on early Islamic history: the hagiographies of around 270 Christians who lost their lives due to their opposition to Islam in the two-century period 660-860 C.E. These "new martyrs" divide into three main categories: born Christians who converted to Islam and then reverted to Christianity; born Muslims who converted to Christianity; and Christians who slandered the Islamic prophet Muhammad.
Sahner devotes much attention to the tricky process of interpreting sacred writings to elicit information about history. He argues convincingly that this is possible and that it helps elucidate the process "whereby the predominantly Christian Middle East of late antiquity became the predominantly Islamic region of today."
He concludes from his research that the rate of conversion of Christians to Islam was distinctly slower and more convoluted than sources written by Muslims suggest:
[I]f the great Muslim annalist al-Tabari were all we relied upon to understand the shape of Middle Eastern society in the post-conquest period, we would come to the erroneous conclusion that nearly everyone in this world had already converted [by 923 C.E.]. Yet this was not the case.
Nor was the conversion of Christians to Islam inevitable; rather, it was "a fragile, contested process."
Sahner's work points to the ongoing and creative effort by historians to piece together the early era of Islam through sources other than Arabic manuscripts, depending mainly on artifacts or on contemporary non-Arabic records. It is a grand undertaking that dates back to Ignaz Goldziher's profound 1880 insight that the vast detail of those Arabic manuscripts does not ensure their accuracy. Bit by bit, the work goes on and the reality of medieval history comes slowly to light.