 Complete the following phrase:  He took part in the October and December 1187 conclaves which elected pope Gregory VIII and pope Clement III. He and cardinal Pietro Diana were sent to mediate between Genoa and Pisa. He also took part in the 1191 conclave which elected pope Celestine III and that of 1198. During summer 1198 he and cardinal Pietro Capuano were chosen as papal legates to follow the crusader army which was about to set out on 