There was a recent incident with the first printing of the Book of Common Prayer (the Church of England's official prayer book) after the death of Queen Elizabeth II.

The BCP includes both references to the current monarch, and to Queen Elizabeth I who ordered it to be compiled. Unfortunately someone at the publisher didn't realize this, and did a find and replace of (among other things) "King" for "Queen" and "Charles" for "Elizabeth", resulting in a page that referred to "Our Sovereign Lord CHARLES, by the grace of God, of England, France and Ireland, King, Defender of the Faith.”

Holy Roman Emperors also pile on the royal titles. King of the Germans, king of Italy, on top of their regular titles. Charles V was king of Germany, Italy, Spain, Lord of the Netherlands, Duke of Burgundy. When he passed half of his titles to his brother Ferdinand, he was also king of Bohemia, Hungary and Croatia.

And yet somehow there's supposed to be only one real king in the Empire (Bohemia).

I'm reading again Henry V, by Shakespeare. The first scene starts with some realpolitik where the archbishop of Canterbury (a Catholic bishop then) distracts the king from passing a law that would strip the Church from a large part of its wealth and lands by making him go to war against France to claim the throne.

The current King of Sweden decided that he had enough and dropped all except King of Sweden from his.

> The kings of England also claimed the title of King of France until 1802, even though they lost the very last enclave on French soil in 1558:

I imagine a future where China badly loses an expansionist war but continues to identify itself as Protector of Tibet for 10 more generations.

Then again I can also imagine a future US Gov rejecting the Confederation of Desantia after it's Bugs Bunny style secession from the US - and continue to use it's archaic name of Florida.

They still hold the Jersey islands where the English monarch is the Duke of Normandy ;)