^According to Sismondi, History of the Italian Republics in the Middle Ages (pg. 29), although Otto II was crowned King of the Romans in 961 and Holy Roman Emperor in 967, he only obtained the Iron Crown at Pavia in late 980, during his descent into Italy, and prior to his celebrating Christmas at Ravenna.
^Although Otto III was crowned Holy Roman Emperor at Rome on 21 May 996, he was crowned King of Italy at Milan prior to the death of Pope John XV in early March 996 - see Comyn, History of the Western Empire, Vol. 1, pg. 123
^enumerated as successor of Henry I who was German King 919–936 but not Emperor.
^enumerated as successor of Conrad I who was German King 911–918 but not Emperor