Livy wrote this History of Rome in Latin in the late first century BC. Book 43 continues the series. Rome, a republic run by a senate and elected officials, is already at war with King Perseus of Macedon, roughly northern Greece, after Eumenes of Pergamum in western Turkey warned the Senate and early campaigns failed to break him.

This year is administration with a body count. Commanders rotate and get scolded. Reports of Roman misconduct in Greece threaten the claim to free the Greeks and the supply lines. Perseus still has a treasury, a phalanx — a dense infantry formation — and the Balkans. Illyria on the Adriatic and the sea-lanes matter as flanks. Cities offer or deny bases. Livy wants courage and discipline enforced even in a winning army. Home politics still assign provinces and honors. Perseus buys time with feelers; Rome answers with pressure. The knockout is coming with Lucius Aemilius Paullus. Until he arrives, the story is logistics, discipline, and Greek opinion.