Why do my British Monarchs Adapt Roman Names?

[Suzaku]

I think it is ridiculous these names! Ugh! If I could only get all moanrchs to be 100% accurate with history! For example, England, the ONLY names allowed should be: William, Edward, Richard, Henry, James, Mary, Elizabeth, George, or maybe one or two I may have missed, but no! No Humphrey! No Thomas! No Augustus Ronald! Please!

I disagree if another Dynasty takes over English/British crown than more names should be able to be drawn upon. Not only that I also feel naming your heir after legendary leaders would've been acceptable, like Augustus, Alexander etc.