“You must decide whether to keep the new eastern provinces Trajan conquered, like Mesopotamia, or give them up to make the empire easier to defend. The army is stretched thin, and some regions are restless. If you keep the land, it shows Roman power, but it may be hard to control. If you withdraw, you might seem weak, but the borders would be stronger and easier to manage.”

Should I keep Trajan’s new eastern conquests, or pull back to stronger, older borders? The caller speaks English, in their own voice, from a short brief of textbook facts, knows nothing of what came later and never tells the outcome; the screen does, after the call. On the live board the telephone rings the whole class: the teacher answers on the room's microphone, and students write to the caller from their phones.