There were a few Edwards, Edgars and Harolds who were kings of England before William, so why was Edward Longshanks not King Edward IV?
Old thread on this I just found https://www.reddit.com/r/AskHistorians/comments/1x4hln/why_did_the_regnal_numbers_for_the_kingdom_of/?utm_source=share&utm_medium=ios_app&utm_name=iossmf
u/Algernon_Asimov