Augustus Drake was born Artorius to a slave woman and an unknown legionnaire. He was separated from his mother almost immediately given to care for to another slave woman until he was old enough to train. From a young age he always thought of the women ho raised him as people. Not that they shouldn't be slaves, he agreed with that readily enough, but rather that they shouldn't be treated as badly as they were. Luckily for young Artorius, he knew how to hide this from his superiors to avoid repercussions. He fought alongside legends at the second battle of Hoover Dam, the Battle for Shady Sands, and many of the purges of NCR rebellion. Those battles only brought him up to the rank of Decanus, as the day he'd be further promoted was the day that Caesar died.
Following the death of Caesar, Lanius took control and declared himself the new Caesar. The legion became stricter, and land became harder to manage as the former Caesar didn't have the time to instill the new government he had wished for. At one point, a group of Legionnaires betrayed the cause and took over Flagstaff, declaring their leader the new Caesar. It took a bloody campaign to get rid of them, though when it was finally over, the West rebelled as well. Lanius died on that Campaign with a throwing spear through the back of his head.
After that, Aurelius of Phoenix was risen to the position. He did manage to win back the West, just to lose more power than Lanius had with another betrayal in the east. By then, Artorius was done traveling around the Mojave for a dying cause. He deserted the next time he saw a chance.
While in hiding from Legionnaires ordered to hunt down fugitives, Artorius found himself in a caravan needing protection. He was paid with caps, food, and any bandits he could keep as slaves. He knew he could've dealt with the wasteland without them, but he enjoyed the caravan guard life. Everything in his life would prove simple for the next two years. That was, until the caravan was killed off during his time on leave to sell his now growing slave population that had been eating up their food. When he came back and found the Caravan no loner existed, he decided he'd travel back into the New Vegas strip.
When he arrived in the New Vegas strip, Artorius saw that the city had fallen to anarchy, with Casino families fighting each other out on the streets daily and no guards to stop it. The Lucky 38 had become home to a splinter group of the Powder Gangers, before being swiftly put down by Artorius at the cost of a few more scars. Mr House's former casino provided more insight into the Legion, as the Caravans had taught Artorius to read and now he could read the books on the first Legions. He'd find out more than he expected. When he finally stopped reading, he'd find himself with the idea to found a better Legion under the name Augustus, or Augustus Drake to the locals. New Vegas wasn't the ideal place to start, so he a few slaves moved into the NCRCF.