It is widely accepted that the eleventh century was pivotal in relations between Jews and Christians. Jews became marginalized socially and economically during this time. They were forced to live separately for their own protection, and they were forced into the position of moneylenders. These developments made them literally and figuratively "other" than the rest of society.
Jewish merchants were among the few who were willing to engage in international trade, and they needed to protect themselves from the dangers of such an occupation. They would necessarily band together and work together to increase their security. Jewish communities connected Jews from all over Europe, and provided a place for them to worship and live as they chose. In the eleventh century, they often became fortified communities to protect Jews from hostile Christians.
This physical separation from the Christian majority made the differences between Christians and Jews even more obvious. A number of Jews resettled in Speyer after a fire was set in their neighborhood in Mainz. The local bishop welcomed them and built a wall to protect their area of the village. This example is the first of its kind, and Leonard Glick writes, "But clearly this charter signaled the onset of a new phase in medieval Jewish history; and despite its friendly language, it indicated that many townspeople did not want Jews in their midst." The wall was erected not to protect Jews from Crusaders, but to protect Jews from the townspeople of Speyer. The Crusades did not begin for another decade.
Already physically detached from much of society, Jews were much more vulnerable to attacks when the religious fervor of the Crusades reached its peak. For one thing, they were easily identifiable. If Jews were segregated into walled neighborhoods, it was much easier for an unruly band of traveling warriors to figure out where the Jews were living. If the Jewish people had been living mixed amongst Christians, someone from out of town would not likely be able to distinguish Jewish homes from Christian ones.
The Speyer charter and subsequent charters granted to Jewish communities in Germany show that by the time of the First Crusade, German Jews were definitely "other" than the rest of society. They were "expected to function independently--that is, to establish themselves as a semienclosed community within a town, to attend to their own legal and administrative needs, and to operate for most intents and purposes as a society within society."
Adding to the decline of the Jewish relationship with Christian society was the changing usefulness of Jewish businessmen. Once, trade had been a largely Jewish occupation, but Christian merchants were becoming more numerous and successful. Jews were pushed out of their economic sphere and relegated to the role of moneylenders. Glick wrote, "By the late twelfth century, Jews in France had become so prominent as moneylenders, and so exclusively dependent on moneylending for survival, that anything said about 'usury'--invariably negative--was bound to call Jews to mind." The usury, or interest rate, was comparable to Christian moneylenders, but moneylending was so tied to Jewish identity that it sparked more bitterness towards Jews. This view of Jews has haunted them and added to their plight more than anything other than the accusation of deicide.
The change in economic status from successful merchants to reluctant moneylenders pushed the Jews further into the margins of society. No one likes to be dependent on others, and owing money to Jews caused much resentment. Why would a lord go out of his way to protect someone he owes a great deal of money to? It would be in his better interest to see that person eliminated if he had no further need for their services and capital.
Christianity held the view of money as the root of all evil, and Germanic society had been one of gift-givers. For Jews to charge usury on loans was a sin. Besides the moral weight of the occupation, moneylending was also an impersonal one. As Glick wrote, "Moneylenders move nothing and handle nothing other than money; they are simply sources of liquid capital--'moneybags' on whom others draw for productive enterprises. Moneylending is thus by its very nature a socially isolated and isolating activity; it neither requires nor even permits entry into the larger world of economic activities and relationships." Hence, Jews were being further marginalized in society by their dependence on moneylending for economic survival.
Under the Carolingians, Jews had been economically successful merchants who enjoyed the protection of the kings. Pepin the Short even went as far as granting Jews the right to hire Christians. This reversed Roman and church law. This precedent was followed by his successors. Charlemagne "recognize[d] Jewish religious requirements. When appearing as a litigant or witness in court, a Jew was to wrap himself from head to foot in his prayer shawl, hold a Hebrew Torah in his right hand and declare" a Jewish oath of innocence. Louis the Pious was even better than his father and grandfather had been to the Jews. He went out of his way to protect Jewish merchants, and even allowed Jews to preach publicly.
Two centuries later, Jews were no longer granted such rights. They were necessarily segregated from Christians for their own protection, and were only tolerated as long as they were useful. Their economic status had declined dramatically, and they were relegated to the precarious position of moneylenders. They were expected to operate independently within their towns. They were placed behind walls. They were not only physically, but also emotionally separated from society. They were truly "other" than the Christian majority, and easily identifiable as such to anyone who might want to harm them. When the First Crusade began, there were enough Christians who wanted to harm them, and Jews were massacred by men who claimed to be doing it for the Lord. As the Nazis knew almost a millennium later, it is far easier to kill somebody if you don't think he is your equal. If he is "other" than you, and lesser than you, it's not as hard to mistreat him. The Jews were "other" than the Christian majority, and the Christian majority of medieval Europe had little difficulty in mistreating the Jews. Jews weren't always killed, but they were always pushed farther into the margins.