Royal Numbering ~ Germany
Germany is a unique example in the topic of monarchy and with numbering their rulers. Unlike Britain and France and other states of Europe, Germany was slow in become a centralized nation-state. For centuries Germany was more of a geographical term than a name attached to a centralized nation state. Similar to France German history has its roots in the old Kingdom of the Franks. The Treaty of Verdun in 843 divided the Charlemagne’s empire. The eastern half of the kingdom retained the imperial title and from this entity evolved the Holy Roman Empire.
Even though Charlemagne is considered the Fist Holy Roman Emperor when he was crown Emperor on Christmas Day 800CE that state was something that developed through the centuries. I remember one historian saying that Charlemagne’s empire, thought to have reestablished the Western Roman Empire, was in reality was a state without a name. In 843 when the empire was divided the monarchs of the eastern half were titled Regnum Francorum Orientalium or Francia Orientalis: the Kingdom of the Eastern Franks. This Kingdom of East Francia lasted from 843 until 911 under the Carolingian Dynasty and the rise of the Ottonian Dynasty.
The imperial title lapsed after the death of Berengar I in 924 and would not be revived until Otto I, Duke of Saxony was crowned Emperor in 962. This is when the majority of historians believe the Holy Roman Empire began. The empire was a loose conglomeration of states with their own leaders who held titles either directly or indirectly from the emperor. The monarchy was elective but in practice it did become hereditary within certain dynasties with the election become a mere formality. The Archdukes of Austria of the Habsburg Dynasty held the title the longest. As territories merged or were annexed the rulers still held their titles and a right to sit in the imperial diet even though they no longer ruled over territory. There is not any discrepancy for the numbering of the emperors but there are some minor discrepancies and inconsistencies for the lesser states.
One of the places where there is a discrepancy in numbering is the Kingdom of Hanover. Prior to its elevation as a kingdom Hanover was an Imperial Electorate within the Holy Roman Empire ruled by a cadet line of the House of Guelph that ruled the various Brunswick duchies. In 1692 Emperor Leopold I installed Duke Ernst August of Brunswick-Lüneburg as Prince-Elector of Hanover. In 1698 Elector Ernst August was succeeded by his eldest son who became Elector Georg Ludwig of Hanover. In 1714 via the provisions of the Act of Settelment of 1701 in England and Scotland Georg Ludwig became King George I of Great Britain. In Hanover and Great Britain the numbering for these King-Electors was the same. In 1727 George I was succeeded by his son as George II and in 1760 his grandson succeeded him as George III.
In 1806 the Holy Roman Empire came to an end and Hanover became part of the Kingdom of Westphalia, a puppet state founded by Napoleon. After the defeat of Napoleon the Congress of Vienna restored George III to his Hanoverian territories and elevated Hanover to a Kingdom. Instead of starting a new numbering of as Kings of Hanover George III still retained his ordinal number. In 1820 George III was succeeded by his son who became George IV of the United Kingdom of Great Britain and Hanover. In 1837 George IV was succeeded by his brother William IV who was known as Wilhelm I of Hanover.
Since succession to Hanover was governed by the Salic Law which barred women from inheriting the throne the personal union between Great Britain and Hanover ended in 1837 with the death of William IV. William IV was succeeded in Great Britain by his niece, Victoria, who reigned in Britain until 1901 and gave her name to the entire era. In Hanover the crown went to another brother of William IV, Ernest Augustus, Duke of Cumberland.
This is where it gets tricky. In my view he should have been been called Ernst August II because the numbering for Hanover began with Ernst August in 1692. However, Ernst August was only an Elector in 1692 and never a King. His son, George I, was the first Hanoverian to hold the royal title of King…although he was a King of Great Britain not a King of Hanover. So it appears that the royal numbering of Hanover follows those with the title of King regardless if the person was not a King of Hanover.