Expansion of Macedonia under Philip II
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 ostensibly 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.
War of the Third Coalition
Historiographers differ on when the War of the Third Coalition began and when it ended. From the British perspective, the war started when Britain declared war on France on 18 May 1803, but it was still on its own. It was not until December 1804 when Sweden entered into an alliance with the United Kingdom, until 11 April 1805 when Russia joined the alliance and only thereafter Austria and Naples–Sicily completed the fully-fledged coalition. No major hostilities between France and any member of the coalition other than Britain occurred until the September 1805 Ulm Campaign. Likewise, no major battles occurred after the Battle of Austerlitz and the signing of the Peace of Pressburg on 26 December 1805, which forced Austria to leave the Third Coalition and cease hostilities against France. Some historiographers conclude that Austria's departure "shattered the fragile Third Coalition" and "ended the War of the Third Coalition". This narrative leaves out the subsequent French invasion of Naples (February–July 1806), which the occupying Anglo-Russian troops hastily evacuated and the remaining Neapolitan forces relatively quickly surrendered. Other scholars argue the southern Italian campaign should be included into the War of the Second Coalition, and criticise ignoring the Mediterranean front by only focusing on land battles in Central Europe and the Trafalgar Campaign.