according to the "cronica" of fra salimbene of parma, nicolò was named bishop in 1211, with the approval of both the emperor otto iv and pope innocent iii. but on 8 april 1213, he is still called bishop-elect. only on 25 september 1213 does he have the full title of bishop of reggio. in piacenza he attempted to broker a peace between the ghibelline sessi and the guelph roberti-fogliani. in 1221 he helped cardinal ugolino (later pope gregory ix) preach the crusade in northern italy. in 1224, he was papal mediator in peace talks between bologna and mantua. in may and june 1230, bishop nicolò dei maltraversi (1211–1243) accompanied an embassy of the emperor frederick ii to pope gregory ix, in the hope of bringing peace between empire and church. on 1 july 1230 he was present in the major church of san germano to witness the papal reconciliation with the emperor. in 1233, he was granted the right to issue coinage by frederick ii. in april 1242, the emperor frederick wrote a letter to bishop maltraversi, expressing his joy at the bishop's success in bringing his nephews and other relatives ("consanguineos et nepotes tuos") back to the imperial side (the ghibellines) and loyalty to the emperor; he urged nicolò to return to him as soon as possible, to assist in some difficult and useful matters.