The first chapter deals with the phrase sacrum imperium in the period 1125–1167. It starts out as a rare occurrence in imperial Italy when the locals sought German imperial assistance and, at the same time, a staple phrase used by Latin diplomats to address the Byzantine emperor. However, Sulovsky shows that after the Second Crusade (1147–1149), the German imperial court increasingly adopted elements of the sacral terminology of the state, as used in the Byzantine east, when dealing with Italian affairs. When Barbarossa’s second Italian campaign (1158–1162) was being planned in early 1157, the term sacrum imperium finally appeared in a document issued by the imperial chancery. However, whereas previous scholars could not tell who the author behind the text was, Sulovsky argues that it was the senior notary Albert of Sponheim, who had introduced other innovations as well, and who had taken part in both the aforementioned crusade and in Frederick’s first Italian expedition as a high-level diplomat. Moreover, Albert adopted sacrum imperium both from the Italian and Byzantine usages to the German one, so that he could convince the letter’s addressee, his fellow crusader Otto of Freising, to join the Italian war.