About the same time, Hilary wrote to Emperor Constantius II a remonstrance against the persecutions by which the Arians had sought to crush their opponents ("Ad Constantium Augustum liber primus", of which the most probable date is 355). Other Historians refer to this first book to Constantius as "Book Against Valens," of which only fragments are extant. His efforts did not succeed at first, for at the synod of Biterrae (Béziers), summoned by the emperor in 356 with the professed purpose of settling the longstanding dispute, an imperial rescript banished the new bishop, along with Rhodanus of Toulouse, to Phrygia.