When Prince Charles becomes King, what name do you think he will use?

[Okay, maybe Mike Johnson is a competent parliamentarian.]

King Arthur II

Actually, I believe it would be King Arthur I, As King Arthur and Camelot is simply a myth.

So? Sweden's had a number of legendary or quasi-historical King Carls.

A better argument against "Arthur II" would be that they restarted numbering Edwards after the Conquest.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

He'll be Duke of Edinburgh if Philip dies.

I'm reasonably sure that's not how royal dukedoms work.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

He'll be Duke of Edinburgh if Philip dies.

I'm reasonably sure that's not how royal dukedoms work.

Charles is Philip's eldest son. Therefore, Charles will be Duke of Edinburgh if Philip dies. William and George are in line to be Duke of Edinburgh as well. Otherwise, William should be king, he's popular than his father. After Diana's death in 1997, Charles has not been forgiven for his past deeds of the 1980s. He is good on climate change issues, however.

I looked it up and if Philip predeceases Elizabeth you might actually be right, but if she predeceases him, the sovereign can't hold peerages.