What is the earliest English fleet that could defeat the Roman invasion fleet of AD 43?
Short answerProbably Henry VII's fleet, because it had cannon. An Armada-era squadron is offered as an even clearer candidate.
NotesHenry VII's fleet is the tentative earliest choice because shipboard cannon would give it a very different engagement capability from Roman vessels. An Armada-era force, even Drake's squadron, is offered as a later example that could probably defeat Claudius's invasion fleet. The answer also places the emergence of the Royal Navy across a longer transition from a monarch's navy to a national fighting institution. The comparison rests on cannon and that institutional development, rather than a demonstrated calculation of opposing fleet strengths.