One such document is Albert of Aachen on the People's Crusade, which focuses on the unsanctioned, disorganized peasant crusades that occurred along with the organized crusader campaigns on Jerusalem. It provides the personal experiences of Aachen, who was in one of these peasant crusades, and provides accounts of the slaughter of several groups of Jews. He describes it as being either "judgment of the Lord" or "some error of mind," and the killings as not only being indiscriminate with no exception. His account also shows the Church being able to achieve little in its attempts to prevent these massacres. Much of the focus of Christian writings of the time, however, was on the efforts to get to Jerusalem, though some accounts talk of the crusaders' distrust of the Byzantine Empire, accounts that show some of the reasoning for the Fourth Crusade and the sack of Constantinople. The Deeds of the Franks, which has an unknown author, is such an account, and has a clear bias against the Byzantines. Many of the writings on later crusades continue to also focus on Jerusalem until the end of the crusades when Jerusalem stops being their focus and the return to stability in Europe does. Many of the secondary sources on this time period question how important the impact of the crusades was on both the Jewish and Christian communities. Robert Chazan believes in the end – both cultures were, in many ways, used to the persecution that was being enacted, and that this was just another step. R. I. Moore, within his book The Formation of a Persecuting Society, argues that the effect on Christians was huge, with their entire society gaining feelings of the need for separation from their Jewish neighbors, which allowed them to persecute further in the future. Ivan G. Marcus in his article The Culture of the Early Ashkenaz argues that the Jews pulled away from the Christian community physically, mentally, and spiritually due to the sheer ferocity and shocking nature of the crusades. All of these and more provide differing opinions on the results of the crusades, but all agree that the crusades caused a separation to occur between the two religions. See also References Crusades Jews, history of