From 961 on, the emperor was usually also king of Italy and Germany, although emperors sometimes appointed their heirs to rule in Italy and occasionally the Italian bishops and noblemen elected a king of their own in opposition to that of Germany. Burgundy was added to this union in 1032, and by the twelfth century the term 'Holy Roman Empire' had come into use to describe it. The union of the crowns of Italy and Germany with that of the so-called 'Empire of the Romans' proved stable. He continued on to Rome, where he had himself crowned emperor on 7 February 962.

In 961, King Otto I of Germany, already married to Queen Adelaide of Italy, invaded the kingdom and had himself crowned in Pavia on 25 December. Until 961, the rule of Italy was continually contested by several aristocratic families from both within and outside the kingdom. Members of the Carolingian dynasty continued to rule Italy until the deposition of Charles the Fat in 887, after which they once briefly regained the throne in 894–896. Charlemagne called himself king of the Lombards and in 800 was crowned emperor in Rome. The southern areas remained under Lombard control, as the Duchy of Benevento was changed into the rather independent Principality of Benevento. In June 774, the kingdom collapsed and the Franks became masters of northern Italy. In 773, Charlemagne, the king of the Franks, crossed the Alps to invade the Kingdom of the Lombards, which encompassed all of Italy except the Duchy of Rome, the Venetian Republic and the Byzantine possessions in the south.

Its original capital was Pavia until the 11th century. It originally comprised large parts of northern and central Italy. The Kingdom of Italy ( Latin: Regnum Italiae or Regnum Italicum Italian: Regno d'Italia German: Königreich Italien), also called Imperial Italy ( Italian: Italia Imperiale, German: Reichsitalien), was one of the constituent kingdoms of the Holy Roman Empire, along with the kingdoms of Germany, Bohemia, and Burgundy.

Heart of Europe by Peter H. Wilson