In 955, Otto won a decisive victory over the
Magyars in the
Battle of Lechfeld.
[34]:707 In 951, Otto came to the aid of
Adelaide, the widowed queen of Italy, defeating her enemies, marrying her, and taking control over Italy.
[35]:214–15 In 962, Otto was crowned Emperor by
Pope John XII,
[34]:707 thus intertwining the affairs of the German kingdom with those of Italy and the Papacy. Otto's coronation as Emperor marked the German kings as successors to the Empire of Charlemagne, which through the concept of
translatio imperii, also made them consider themselves as successors to Ancient Rome. Additionally, in 963, Otto deposed the current pope John XII and chose
Pope Leo VIII as the new pope (although John XII and Leo VIII both claimed the papacy until 964, when John XII died).
This also renewed the conflict with the
Eastern Emperor in Constantinople, especially after Otto's son
Otto II (r. 967–83) adopted the designation
imperator Romanorum. Still, Otto formed marital ties with the east when he married the Byzantine princess
Theophanu.
[34]:708
Their son,
Otto III, came to the throne only three years old, and was subjected to a power struggle and series of regencies until his age of majority in 994. Up to that time, he had remained in Germany, while a deposed Duke,
Crescentius II, ruled over Rome and part of Italy, ostensibly in his stead.
In 996 Otto III appointed his cousin
Gregory V, the first German Pope.
[37] A foreign pope and foreign papal officers were seen with suspicion by Roman nobles, who were led by
Crescentius II to revolt.
Otto III's former mentor
Antipope John XVI briefly held Rome, until the
Holy Roman Emperor seized the city.
[38]
Otto died young in 1002, and was succeeded by his cousin
Henry II, who focused on Germany.
[35]:215–17
Henry II died in 1024, and
Conrad II, first of the
Salian Dynasty, was elected king only after some debate among dukes and nobles. This group eventually developed into the college of
Electors.