it always amuses me to remember what a fiasco Julius Caesar's first attempt to conquer Britain was.
Romans were terrible sailors (they're used to the calm Mediterranean, after all), and it was stormy (the boats carrying all of the cavalry had to turn back!), and they reached shore _right_ in the middle of the white cliffs of Dover, and of course they couldn't land there or anywhere near there, so they had to sail down the coast for miles, and it didn't get much better from there