I due gladiatori
The twins of the recently departed Marcus Aurelius fight it out to see who will become emperor of Rome.
Starring Richard Harrison, Moira Orfei, Giuliano Gemma, Mimmo Palmara, Alberto Farnese, Ivy Holzer, Piero Lulli, Gianni Solaro, Álvaro de Luna
Watch "I due gladiatori" from streaming services Amazon, Tubi TV released in 1964. It's a drama and action & adventure movie, and has a rating of 5 out of 10 from Imdb which is fairly low for this kind of movie.