How do numbered names work, e.g. the "II" in William II?

How come there are several people named William II? How come William II is also William III and William IV? What is the official name of this numbering scheme?

  • 3
    There is no generic rule. If you have a father, son, and grandson each with the same name, you may have "William III". If you have a king or pope who has the same name as a predecessor, you may have "William III". For example, the famous King James (James Stewart) was known as James VI in Scotland but as James I as king of England. Commented Jul 21, 2016 at 14:09
  • nth king of X bearing this name and mth king of Y, kth Duke of Z. Some title generally will be the primary, but it always relates to the country ruled. William II could be an English king, a Dutch statholder or a German emperor without additional context. August the Strong was August II of Poland and August of Saxony..
    – Chieron
    Commented Jul 21, 2016 at 14:23

2 Answers 2


I am restricting this to rulers titles; there are some families were one of the sons gets the name of the father and so use numerals, but they are out of scope.

It is not "William I" or "William I", but "William I of Germany" and "William I of England". The number is used to indicate between different holders of the same title and same name.

So, if we are talking about English Monarchy, the numbering of Georges will count only those who were Kings of England (sorry, G. Washington).

Also, since the same person could hold more than one title, it is possible that he was the first person of that name to hold title A and the fifth person of that name to hold title B. So, it was Charles I of Castille and V of Germany (because there was no previous king named Charles in Castille and there were four previous German Emperor named Charles).

Things to take into account:

  • Many old rulers would not use the number as part of his title (so, "William I of England" styled himself "William, King of England", not "William I")

  • There are a number of strange cases, usually due to bad historiography. One of the most notorious is that of the numbering of the Swedish Charles (https://en.wikipedia.org/wiki/Charles_VII_of_Sweden).

  • 4
    "William the Conqueror" was William I, not II. He wouldn't have referred to himself as either 'William I' or 'William the Conqueror', but as "William, king of England". "The Conqueror" was a nickname given him by later historians. "William the Bastard" was a nickname actually used in his lifetime and afterwards (although presumably not to his face, at least in later life).
    – fred2
    Commented Jul 21, 2016 at 19:35
  • 6
    On the other hand, it was the habit even in the high middle ages to refer to kings by their number when referring to a previous monarch. So a charter from 1121 refers to "dominis nostris WIllelmo primo et Willelmo secundo" (Pipe Rolls, vol. 10, 14), but the current monarch would still be "Willelmus Rex Angliae".
    – fred2
    Commented Jul 21, 2016 at 20:02
  • 1
    @fred2 Corrected in line with your comments, thank you.
    – SJuan76
    Commented Jul 22, 2016 at 11:40
  • The classic example is King James the First and Sixth: James the First of England, and James the Sixth of Scotland (already) at his ascension to the English throne. Commented Jul 22, 2016 at 21:49
  • "There are a number of strange cases, usually due to bad historiography." My favourite is that the French monarchs either side of Odo are two different men both numbered Charles III. By contrast, there was no Charles I, unless you count Charlemagne. After the second Charles III, numbers continued as Charles IV.
    – J.G.
    Commented Sep 22, 2022 at 19:34

The "numbers game" can be quite complex, due to historians preferring to continue the bad habits of earlier historians since correcting confused numbering may cause more confusion among those used to the bad numbering system.

If a monarch had enough realms, he might be, for a totally fictional example, king Kong I of Bulmania, Duke Kong II of Herzogia, King Kong III of Ruritania, Prince Kong IV of Guastarkia, Count Kong V of Downia, and so on. And in each of those realms that remained an independent state in the age of nationalism, history books would list him by his number for that land. And historians in other lands that had never been ruled by him would probably choose which number to use based on the current importance of that realm.

For example, Holy Roman Emperors and kings of the Romans are listed by their numbers as Kings of Germany as used by German historians. And that usually results in using their correct numbers as emperors. But since in the Carolingian era there were a few kings of Germany who were not emperors and a few emperors who were not kings of Germany, there are a few problems. The emperors started using numbers in their own documents in the reign of Emperor Henry III, for example but he is called Henry IV in history books because of his numbering as king of Germany. Emperors named Henry actually used a number that is one less than their number in the history books.

Because mere kings rarely used numbers in their own documents and thus made them official until the Renaissance and later, and because it was often hard to decide if someone counted as a previous monarch, the numbering of monarchs of many lands is confusing and illogical.

For example, in the 14th century England, in the reign of King Edward of Windsor, son of King Edward of Caernarfon, son of King Edward Longshanks, and father of Edward the Black Prince who was presumed to be the next king, people started writing about them as Edward III, son of Edward II, son of Edward I. And centuries later when using numbers in history books was common, they continued to call those three Edwards Edward I, Edward II, and Edward III. Despite the fact that previous English history included King Edward the Elder, King Saint Edward the Martyr, and King Saint Edward the Confessor.

And King Edward VII and King Edward VIII continued to number themselves as if Edward Longshanks was the first King Edward of their realm, even though in 1707 the kingdoms of England and Scotland were merged to form a new kingdom, Great Britain, which merged with the kingdom of Ireland in 1801 to form the new United Kingdom of Great Britain and Ireland.

  • Carlovingian? That's a new one.
    – CGCampbell
    Commented Jul 22, 2016 at 13:24
  • 3
    "which merged with the kingdom of Ireland to form the new United Kingdom." Not quite, it was actually the "United Kingdom of Great Britain and Ireland". Since Eire split away, it is the "United Kingdom of Great Britain and Northern Ireland". (We just like to confuse foreigners! ;) )
    – TheHonRose
    Commented Jul 22, 2016 at 15:33
  • CGCampbell - I corrected the spelling. Commented Jul 23, 2016 at 17:17
  • TheHonRose - Okay, I wrote the full title of the new kingdom of 1801. When Was the title changed to "United Kingdom of Great Britain and Northern Ireland"? Commented Jul 23, 2016 at 17:19
  • @M.A.Golding The split of Ireland into Eire and Northern Ireland was in 1922 - but the title of the UK wasn't changed to reflect the split until 1953 en.wikipedia.org/wiki/Royal_and_Parliamentary_Titles_Act_1927
    – user13123
    Commented Jul 25, 2016 at 2:08

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