Roman Emperor Frederick II resulted in protests, ultimately overcome with the help of Henry and the Pope, and in the 1250s Henry's crusading tithes faced similar resistance. Jewish policies The Jews in England were considered the property of the Crown, and they had traditionally been used as a source of cheap loans and easy taxation, in exchange for royal protection against antisemitism. The Jews had suffered considerable oppression during the First Barons' War, but during Henry's early years the community had flourished and became one of the most prosperous in Europe. This was primarily the result of the stance taken by the regency government, which took a range of measures to protect the Jews and encourage lending. This was driven by financial self-interest, as they stood to profit considerably from a strong Jewish community in England. Their policy ran counter to the instructions being sent from the Pope, who had laid out strong anti-Jewish measures at the Fourth Lateran Council in 1215; William Marshal continued with his policy despite complaints from the Church. In 1239 Henry introduced different policies, possibly trying to imitate those of Louis of France: Jewish leaders across England were imprisoned and forced to pay fines equivalent to a third of their goods, and any outstanding loans were to be released. Further huge demands for cash followed – £40,000 was demanded in 1244, for example, of which around two-thirds was collected within five years – destroying the ability of the Jewish community to lend money commercially. The financial pressure Henry placed on the Jews caused them to force repayment of loans, fuelling anti-Jewish resentment. A particular grievance among smaller landowners such as knights was the sale of Jewish bonds, which were bought and used by richer barons and members of Henry's royal circle as a means to acquire lands of lesser landholders, through payment defaults. Henry had built the Domus Conversorum in London in 1232 to help convert Jews to Christianity, and efforts intensified after 1239. As many as 10 percent of the Jews in England had been converted by the late 1250s in large part due to their deteriorating economic conditions. Many anti-Jewish stories involving tales of child sacrifice circulated in the 1230s–50s, including the account of "Little Saint Hugh of Lincoln" in 1255. The event is considered particularly significant, as the first such accusation endorsed by the Crown. Henry intervened to order the execution of