I have actually written an article on the Arthur Dudley myth - see https://www.elizabethfiles.com/the-arthur-dudley-myth/3298/ - Arthur definitely existed but most historians do not believe that he was the illegitimate son of Elizabeth and Robert Dudley. One theory, put forward by Sarah Gristwood, is that he may have been an English agent. She points out that Walsingham made good use of “agents provocateurs”, sending them undercover to gather information on foreign enemies, and that this may explain why Arthur Dudley suddenly disappears from history, perhaps he escaped and resumed his own identity.
You can read the full story in my artciel.
Can you tell me about the “secret marriage” of Princess Margaret Douglas to Lord Thomas Howard (1511-1537) — and the birth of Robert Howard (Jan 1537-1598) in Syon House?