The advance of the Norman conquest of southern Italy constituted a threat to the possessions of both the Byzantine Empire and the papacy, each of which sought the support of the other. Accordingly, conciliatory letters, the texts of which have not been preserved, were written to the pope by the emperor and Cerularius. In his January 1054 reply to the emperor, "Quantas gratias", Leo IX asks for his assistance against the Normans and complains of what the pope saw as Caerularius's arrogance. In his reply to Caerularius, he upbraided the patriarch for trying to subject the patriarchs of Alexandria and Antioch to himself and for adopting the title of Ecumenical Patriarch and insisted on the primacy of the see of Rome.