[...] At what stage did France separate from the above and became Frankenreich and separately Heilig Römischer Reich i.e. two rulers.?????
It is not known what is agreed, but Charlemagne travels to Rome in 800 to support the pope. In a ceremony in St Peter's, on Christmas Day, Leo is due to anoint Charlemagne's son as his heir. But unexpectedly (it is maintained), as Charlemagne rises from prayer, the pope places a crown on his head and acclaims him emperor.
Charlemagne expresses displeasure but accepts the honour.
The displeasure is probably diplomatic, for the legal emperor is undoubtedly the one in Constantinople. Nevertheless this public alliance between the pope and the ruler of a confederation of Germanic tribes now reflects the reality of political power in the west. And it launches the concept of the new Holy Roman Empire which will play an important role throughout the Middle Ages. The Holy Roman Empire only becomes formally established in the next century. But it is implicit in the title adopted by Charlemagne in 800: 'Charles, most serene Augustus, crowned by God, great and pacific emperor, governing the Roman empire.'
The coronation of Otto I by pope John XII in 962 marks a revival of the concept of a Christian emperor in the west. It is also the beginning of an unbroken line of Holy Roman emperors lasting for more than eight centuries. Otto I does not call himself Roman emperor, but his son Otto II uses the title - as a clear statement of western and papal independence from the other Christian emperor in Constantinople.
Otto and his son and grandson (Otto II and Otto III) regard the imperial crown as a mandate to control the papacy. They dismiss popes at their will and instal replacements more to their liking (sometimes even changing their mind and repeating the process). This power, together with territories covering much of central Europe, gives the German empire and the imperial title great prestige in the late 10th century. But subservience was not the papal intention in reinstating the Holy Roman Empire. A clash is inevitable.
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