Who Was Tertius / Tercius?

[Epictetus]

You wanna know if they're true or not. The stories about me? Did you ever notice with stories like that, everyone says they heard it from someone who was there. Then when you ask that person, they say *they* heard it from someone who was there. It's nothing new really. I bet if you went back two thousand years, you'd hear a couple centurions standing around yakking about how Tertius lopped off the heads of some Carthaginian prisoners.

To me, it seems from the context that Tertius is not a real person, and this is entirely the point. It is simply a figure with a reputation built upon something unclear. If it was a real person, with a reputation built upon real eyewitnesses, the point would be lost and the conversation meaningless. The seemingly generic name "Tertius" fits this perfectly, and that is why they didn't use "Scipio" or "Pompey" or "Caesar" - all real people with real backgrounds to their reputations. They want an air of mystery and uncertainty.