gregory took refuge in castel sant'angelo, and refused to entertain henry's overtures, although the latter promised to hand over guibert as a prisoner if the pope would consent to crown him emperor. gregory, however, insisted as a necessary preliminary that henry should appear before a council and do penance. the emperor, while pretending to submit to these terms, tried hard to prevent the meeting of the bishops. a small number however assembled, and, in accordance with their wishes, gregory again excommunicated henry.