Without reading other answers, that certainly makes more sense than mine, I would take a cake. Like the best cake i ever ate in my life and eat it all immediately after being sent in Roman era. Because if I'm getting fucked at least let's enjoy a last meal and nothing else i could take would matter. Guns, medicines,..? It would all run out anyway and it wouldn't make me king of something.
Edit: and also a bottle of good wine because Roman win tasted like vinegar.