How did Philip II become involved in the Third Sacred War?

Philip II of Macedon became involved in the Third Sacred War (355–346 BCE) primarily through an invitation from the Thessalian city of Larissa.1

The war originated from a conflict between Thebes and Phocis, with the Phocians seizing the temple treasure at Delphi to fund a powerful mercenary army. As the conflict progressed, the Phocian leader Onomarchus formed alliances with the rulers of Pherae in Thessaly, prompting other Thessalian cities to seek external assistance against them.1

Philip’s intervention led to his defeat by the Phocians in their first encounter, but he subsequently reversed this at the Battle of the Crocus Field in 352 BCE. This victory allowed Philip to take control of Thessaly, acquire its ports and revenues, and gain the support of the Thessalian League. Ultimately, Philip used his role in the war to establish himself as a dominant power in Greece, eventually securing membership in the Delphic Amphictyony and positioning himself as a leader of the Greek states.12