The Jewish communities of Spain, owing to their social isolation and to the religious and political regulations imposed upon them, had always formed groups apart from the rest of the population. The authority exercised by their own rabbis and the system of tax-collection by the heads of the congregations for the administration of communal affairs, placed them almost completely without the jurisdiction of the government of the country; and, as a result, they soon came to be dealt with by the officials not as subjects amenable to the general law of the land, but as collective bodies with special privileges and special duties.