Expansion of Macedonia under Philip II a significant problem, blocking the main route into Greece. However, a second route into central Greece was available. In 480 BC, during the Battle of Thermopylae, the Persian king Xerxes had sent his army via a mountain track (the "Anopea") to outflank the pass. From this track, on the western side of Mount Kallidromon, another road led off and descended in Phocis. In 480 BC, a thousand Phocian troops were stationed above Thermopylae to guard the road and prevent a Persian assault on Phocis (though they notably failed to prevent the Persians using "Anopea"). However, in 339 BC, the Greeks
Greece in the 5th century BC Peloponnese, winning battles at Naupactus (429 BC) and Pylos (425 BC). But these tactics were not able to provide either side with a decisive victory. After several years of inconclusive campaigning, the moderate Athenian leader Nicias concluded the Peace of Nicias (421 BC). In 418 BC, however, hostility between Sparta and the Athenian ally Argos led to a resumption of fighting. At Mantinea Sparta defeated the combined armies of Athens and her allies. The resumption of fighting brought the war party, led by Alcibiades, back to power in Athens. In 415 BC Alcibiades persuaded the Athenian Assembly to launch a