[3] He and Bishop Tedaldo of Piacenza disputed for a number of years over the possession of Brugneto, and he appeared by proxy before an examination committee of cardinals.

[5] Pope Lucius III appointed Petrus cardinal deacon of San Nicola in Carcere in the consistory of the Ember Days of March 1185.

The consistory was held in Verona, where Lucius and the papal curia were being besieged by the Emperor Frederick Barbarossa, with whom the pope had had a serious falling out.

After twenty months as a virtual prisoner in Verona, the new pope, Urban III (Umberto Crivelli) escaped with the cardinals in the second half of September 1187, and made for Ferrara.

[10] During the Ember Days of Lent 1188, Clement III made Petrus Dianus a cardinal priest, with the titulus of Santa Cecilia in Trastevere.

[11] During his brief pontificate in the last quarter of 1187, Pope Gregory VIII, though shaken by the loss of Jerusalem to Saladin and the near-collapse of the Latin Church in the Holy Land, had already begun to work toward bringing aid to the Crusaders.

[12] His effort was instantly taken up by Pope Clement III, who, in February 1188, ordered the Pisatans and the Genoans each to choose representatives to negotiate and swear their oaths.

[14] On 7 July, the legates, sitting in Lucca, were able to announce that the two parties had agreed a peace between them, which was confirmed by themselves on the authority of Clement III.

[17] In April 1189, Cardinal Petrus was in Padua, where he appointed Bishop Stephen of Ferrara to handle a case between an abbess and a prior.

In response, on 27 April, Pope Celestine sent two cardinals to meet the emperor, who was in the Marches at the moment, to preach the crusade, Petrus of Santa Cecilia and Graziano of Ss.

[23] In August, Petrus and Cardinal Giovanni of S. Stefano were invited to Germany to preach the crusade; his work carried him to Worms and into Saxony.

Pope Celestine had died on 8 January 1198, and after his funeral on the same day, the cardinals elected Lothar dei Conti, who chose the name Innocent III.