Louis II of Italy
the King of Italy and Roman Emperor from 844, co-ruling with his father Lothair I until 855, after which he ruled alone.
Louis's usual title was imperator augustus , but he used imperator Romanorum after his conquest of Bari in 871, which led to poor relations with Byzantium. He was called imperator Italiae in West Francia while the Byzantines called him Basileus Phrangias. The chronicler Andreas Bergomatis, who is the main source for Louis's activities in southern Italy, notes that "after his death a great tribulation came to Italy."