allowed to return after a few years. The Spanish expulsion was succeeded by at least five expulsions from other European countries, but the expulsion of the Jews from Spain was both the largest of its kind and, officially, the longest lasting in western European history. Over the four-hundred-year period during which most of these decrees were implemented, the causes of expulsion gradually changed. At first, expulsions of Jews (or absence of expulsions) were exercises of royal prerogatives. Jewish communities in mediaeval Europe often were protected by and associated with monarchs because, under the feudal system, Jews often were a monarch's only reliable source of taxes. Jews further had reputations as moneylenders because they were the only social group allowed to loan money at a profit under the prevailing interpretation of the Vulgate (the Latin translation of the Bible used in Roman Catholic western Europe as the official text), which forbade Christians to charge interest on loans. Jews, therefore, became the lenders to and creditors of merchants, aristocrats, and even monarchs. Most expulsions before the Alhambra Decree were related to this financial situation: to raise additional monies, a monarch would tax the Jewish community heavily, forcing Jews to call in loans; the monarch then would expel the Jews; at the time of expulsion, the monarch would seize their remaining valuable assets, including debts owed them by other subjects of the monarch and, in some instances, by the monarch himself. Expulsion of the Jews from Spain was thus an innovation not only in scale but also in its motivations. Ferdinand and Isabella Hostility towards the Jews in Spain was brought to a climax during the reign of the "Catholic Monarchs," Ferdinand and Isabella. Their marriage in 1469, which formed a personal union of the crowns of Aragon and Castile, with coordinated policies between their distinct kingdoms, eventually led to the final unification of Spain. Although their initial policies towards the Jews were protective, Ferdinand and Isabella were disturbed by reports claiming that most Jewish converts to Christianity were insincere in their conversion. As mentioned above, some claims that conversos continued to practice Judaism in secret (see Crypto-Judaism) were true, but the "Old" Christians exaggerated the scale of the phenomenon. It was also claimed that Jews were trying to draw conversos back into the Jewish fold. In 1478, Ferdinand and Isabella made a formal application to Rome to set up an Inquisition in