Some modern critics have argued that the "Pirenne Thesis" erred on two counts: by treating the Carolingian realm as a Roman state and by overemphasizing the effect of the Islamic conquests on the Byzantine or Eastern Roman Empire. Other critics have argued that while Pirenne was correct in arguing for the continuity of the Empire beyond the sack of Rome, the Arab conquests in the 7th century may not have disrupted Mediterranean trade routes to the degree that Pirenne argued. Michael McCormick in particular has argued that some recently unearthed sources, such as collective biographies, describe new trade routes. Moreover, other records and coins document the movement of Islamic currency into the Carolingian Empire. McCormick has concluded that if money was coming in, some type of goods must have been going out – including slaves, timber, weapons, honey, amber, and furs.
