Being a historian in the Roman Empire was much more like being a storyteller than what we would consider a historian today. Unless you were wealthy on your own, you'd need a patron, and if you were good you could expect some degree of social prestige. I'll use Livy as an example. He was a member of the upper class, and he wrote "History of Rome" (Ab Urbe Condita), a complete history of the city of Rome from its founding to the death of Augustus. His historiography is highly questionable by modern standards; he drew heavily from unsubstantiated legends about the founding of Rome and the early years of the city. He is greatly concerned with reinforcing the values of the Roman Republic; most of his stories have some sort of moral angle. But despite his penchant for Republican values, he supported the narrative of Augustus' legitimacy: he tells the story of the arrival of Aeneas in Latium and connects the Julio-Claudian line to this ancestral founder. Livy was wildly popular during his lifetime, his book was published widely, and he was invited to speak on many occasions.