Plebeians and their letters

[Aetius Helvius Merula]

You're right, Jan, I did pretty much answer my own question. I guess I'd unconsciously assumed every citizen could read, even knowing that education depended on your circumstances and access, in the days before universal schools. But I'm glad I asked; I've been researching the civilian side of Rome as well as the army, but this is one topic that didn't occur to me before.