Julius Caesar was the best general of his age and a hell of a PR agent.
He wrote the official account of his Gallic wars himself, in the third person, and sent it home to the voters paying for them.
His war reports are brilliant writing, but historians take them with a grain of salt.
But this week, a burned wall under a Paris hospital proved him right.
In 52 B.C., a Roman army was closing in on Lutetia, the Gallic town on an island in the middle of the Seine.
Caesar wrote that the Parisii set fire to every house and cut both bridges rather than hand it over. For 2,000 years nobody could prove it, or even say where the town stood.
Archaeologists digging in the courtyard of the Hôtel-Dieu, a short walk from Notre-Dame, found a 65-foot Celtic wall of stone and timber.
Its facing was charred. Next to it lay burnt seeds, a burned wooden building, and a Gallic spearhead at the foot of the wall.
"For centuries, the location of Lutetia has been debated," said Stéphane Deschamps, the regional archaeology curator.
Parisians have been walking over it on their way to see a doctor since the 600s.
The Parisii burned Lutetia to keep Rome out. Two thousand years later, the scorch marks gave it away.
Tomorrow on Past Passport, I'll tell the rest: the Roman army crossing the Seine at night in a thunderstorm, and the old Gallic chief who refused to run.