Just to be clear, I am referring to the Byzantine emperor who reigned for a few months in 641, not the Western Roman usurper. Constantine III was made co-emperor by Heraclius in 613, and seemed a competent character. What if he had not died of tuberculosis just a few months into his reign, and was able to keep his throne? How would he deal with the Arabs? Could he push them out of Egypt? Can he regain the duchy of Benevento? How would he deal with Valentinius and Heraklonas?