 Complete the following phrase:  During the Middle Ages in Europe persecutions and formal expulsions of Jews were liable to occur at intervals, although it should be said that this was also the case for other minority communities, regardless of whether they were religious or ethnic. There were particular outbursts of riotous persecution during the Rhineland massacres of 1096 in Germany accompanying the lead-up to the First Crusade, many involving the crusaders as they travelled to the East. There were many local expulsions from cities by local rulers and city councils. In Germany the Holy Roman Emperor generally tried to restrain persecution, if only for economic reasons, but he was often unable to exert much influence. In the 