Battle of Crocus Field
The Third Sacred War (often just called 'the' Sacred War) broke out in 356 BC, and would present Philip with his first real opportunity to expand his influence into the affairs of central and southern Greece. The war was caused by the refusal of the Phocian Confederation to pay a fine imposed on them in 357 BC by the Amphictyonic League, a pan-Greek religious organisation which governed the most sacred site in Ancient Greece, the Temple of Apollo at Delphi. Behind the religious element, there probably lay a display of "realpolitik" in bringing charges against the Phocians, instigated by the Thebans. At this time, Thebes controlled a majority of the votes in the council, and at the autumn meeting in 357 BC, the Thebans were able to have both the Phocians (for the cultivation of the sacred land) and the Spartans (for occupying Thebes some 25 years previously) denounced and fined. Since the fines for both parties were "unjustifiably harsh", the Thebans probably expected neither party to pay, and thus to be able to declare a "sacred war" on either.
Third Sacred War
After agreeing to the peace terms with Macedonian ambassadors in April, the Athenians dispatched a second embassy to Macedon, to extract the peace oaths from Philip; this embassy travelled to Pella at a relaxed pace, knowing that Philip was away on campaign against the Thracian king Kersebleptes. When they arrived, the Athenians (again including Demosthenes and Aeschines) were rather surprised to find embassies from all the principle combatants in the Sacred War were also present, in order to discuss a settlement to the war.