CRISTIANO, archbishop of MAINZ — The monk Frederick offers a book to Archbishop C. Pontifical of Mainz (1167–83). Paris, Bibliothèque Nationale, ms. lat. 946, fol. 127.
He was ambassador to Constantinople. Upon his return to Italy he failed to win Genoa and Tuscany for the emperor; better success attended him in the Romagna, except Ancona. With Venetian help he laid a hard siege to it, but without success (April–October 1173). Engaged in central Italy, he could not hasten to the aid of Barbarossa at Legnano. He then advised the emperor to make peace with Alexander III and conducted the envoys sent to negotiate it to Anagni (1176). The following year, at Venice, he abjured the schism and was absolved from excommunication. Remaining in central Italy to safeguard imperial policy, he set about reconciling the surviving schismatics with Alexander III and forced the antipope Callistus III to beg forgiveness. He took part in the Third Lateran Council of 1179. Taken prisoner by his enemies (September 1179), he bought his freedom with a heavy ransom and the promise to leave Italy (1180), which he afterward failed to keep. Invoked by Lucius III against the Romans at war with the papal town of Tusculum, he died there of fever on 25 August 1183.