What if Roman Empire Had Two Co-Emperor's From Start?
Was reading about the co emperor's Marcus Aurelius-Lucius Verus and got the idea of having Rome with two Emperor's from the beginning. Augustus could have in theory left the empire to Agrippa's children Gaius and Lucius, had they lived, or to both Tiberius and Drusus the Elder, had he lived. What would be the implications? Would this be more effective or less effective? Note this scenario implies, I know its a stretch, that the various emperors are do not to kill each other for power.
Some interesting pairings I was thinking of:
Gaius and Lucius
Tiberius and Drusus the Elder
Germanicus and Drusus the Younger
Caligula and Gemellus
Nero and Britannicus