Plutarch wrote Parallel Lives, paired Greek and Roman biographies of character, virtue, and vice. This life is Marcus Junius Brutus, set beside Dion. The action is late-Republic Rome — a city run by a senate and elected officials, not a king — then the wars that followed in Greece.

Brutus had Cato for an uncle and Julius Caesar for a benefactor. He took the lead on the Ides of March, the day Caesar was stabbed, because the name Brutus still meant the ancestor who had driven out the Tarquins, Rome’s last kings. The daggers made a corpse and not a Republic. At Philippi, in northern Greece, he won the first battle and lost the second. He fell on his sword in the night. Mark Antony had the body wrapped in purple. Two philosophical assassins, two aftermaths that never became constitutions: that is the story you walk into.