Hey Julius! Seems like my black magic worked and I raised you from the dead!

Remember that you became proconsul (a person who acts on behalf of the consul) of two provinces after your normal consulship ended? You were also given command over yet another province when the governor suddenly died. The provinces you controlled compromised of what is now Northern Italy.

This initially gave you command over four legions, but as governor/proconsul you was able to levy auxillary units and even legions as you saw fit. If I recall correctly, you raised four extra legions so that would put the counter on 8 legions, double what he started with. It's important to note that legions are the more elite heavy infantry of Rome, consisting of only Roman citizens with auxillaries making up the remainder of the army. In fact, for most of the Imperial period, your average Roman army consisted of mainly auxiliaries and then some legions. Their cavalry was almost completely comprised of auxillary units.

Usually these soldiers were levied/conscripted. But, since Rome was still a Republic at that moment and after the Marian reforms, one could also voluntarily join the army and become a professional soldier. By 88BC a substantial amount of soldiers were volunteers rather than conscripts, but it was definitely not unheard of.

But, screw sending over paperwork to the senate, because you, my silly Julius, didn't have the right to conquer Gaul and invade Britain. Or at least not the explicit permission of the Senate to do so. But because you were proconsul which allowed you immunity from prosecution, you did it anyways. Important to note is that it's customary to only get this title for one year, but you got it for a whopping five years and it got extended for another five. So yeah, you had to levy the people living in your province or get volunteers by various promises considering you couldn't count on the senate for much help, if any at all. Heck, around 50BC they even asked you to resign command of your army and were offended when you told them you would if Pompey did the same. Then, the Senate threatened to declare you enemy of the people if you didn't disband your army immediately. This was actually an illegal political act since you were entitled to keep your army until your term expired, but hey, just another day in Rome!