A letter was sent to Corinth saying that the Achaean troops had to leave the city. Aratus himself received the letter, but sent the couriers on their way. Plutarch also reports, confusingly, that Aratus was a prisoner on a Macedonian boat carrying him back to Corinth. While this information is contradictory and cannot be entirely correct, the outcome was the same: Aratus organised a punitive expedition into Attica, but turned back before reaching the walls of Athens. The reasons are unclear. His army may have been defeated; or he may have returned to the Peloponnese as he knew that Bithys' army was approaching from the south on its way back to Macedon. Macedon's King Demetrius was later killed in battle against invading Celtic tribes.