I admit I was quite surprised at the ‘Prince Philip’ investiture development. I thought I was quite well-versed in the title stuff.
He was BORN a Prince (of both Greece and Denmark) so I think I assumed he always had the title.
Even if he wasn’t allowed to use that title in the UK, I’m very surprised that he wasn’t conferred as a British Prince as soon as he married Princess Elizabeth or at LEAST when she ascended the throne.