Second Persian invasion of Greece in the context of "Delian League"

Archaic Greece was the period in Greek history lasting from c. 800 BC to the second Persian invasion of Greece in 480 BC, following the Greek Dark Ages and succeeded by the Classical period. In the archaic period, the Greeks settled across the Mediterranean Sea and the Black Sea: by the end of the period, they were part of a trade network that spanned the entire Mediterranean.

The archaic period began with a massive increase in the Greek population and of significant changes that rendered the Greek world at the end of the 8th century entirely unrecognizable from its beginning. According to Anthony Snodgrass, the archaic period was bounded by two revolutions in the Greek world. It began with a "structural revolution" that "drew the political map of the Greek world" and established the poleis, the distinctively Greek city-states, and it ended with the intellectual revolution of the Classical period.

The Battle of Plataea was the final land battle during the second Persian invasion of Greece. It took place in 479 BC near the city of Plataea in Boeotia, and was fought between an alliance of the Greek city-states (including Sparta, Athens, Corinth and Megara), and the Achaemenid Empire of Xerxes I (allied with Greek states including Boeotia, Thessalia, and Macedon).

At the preceding Battle of Salamis, the allied Greek navy had won an unlikely but decisive victory, preventing the conquest of the Peloponnesus region. Xerxes then retreated with much of his army, leaving his general Mardonius to finish off the Greeks the following year. In the summer of 479 BC, the Greeks assembled a huge army and marched out of the Peloponnesus. The Persians retreated to Boeotia and built a fortified camp near Plataea. The Greeks, however, refused to be drawn into the prime terrain for cavalry around the Persian camp, resulting in a stalemate that lasted eleven days.

Hoplites (/ˈhɒplaɪts/ HOP-lytes) (Ancient Greek: ὁπλῖται, romanized: hoplîtai [hoplîːtai̯]) were citizen-soldiers of Ancient Greek city-states who were primarily armed with spears and shields. Hoplite soldiers used the phalanx formation to be effective in war with fewer soldiers. The formation discouraged the soldiers from acting alone, for this would compromise the formation and minimize its strengths. The hoplites were primarily represented by free citizens – propertied farmers and artisans – who were able to afford a linen or bronze armour suit and weapons (estimated at a third to a half of its able-bodied adult male population). Some states maintained a small elite professional unit, known as the epilektoi or logades ('the chosen') because they were picked from the regular citizen infantry. These existed at times in Athens, Sparta, Argos, Thebes, and Syracuse, among other places. Hoplite soldiers made up the bulk of ancient Greek armies.

In the 8th century BC, Greek armies started to adopt the phalanx formation. The formation proved successful in defeating the Persians when employed by the Athenians at the Battle of Marathon in 490 BC during the First Greco-Persian War. The Persian archers and light troops who fought in the Battle of Marathon failed because their bows were too weak for their arrows to penetrate the wall of Greek shields of the phalanx formation. The phalanx was also employed by the Greeks at the Battle of Thermopylae in 480 BC and at the Battle of Plataea in 479 BC during the Second Greco-Persian War.

The kingdom of Macedonia was an ancient state in what is now the Macedonian region of northern Greece, founded in the mid-7th century BC during the period of Archaic Greece and lasting until the mid-2nd century BC. Led first by the Argead dynasty of kings, Macedonia became a vassal state of the Achaemenid Empire of ancient Persia during the reigns of Amyntas I of Macedon (r. 547 – 498 BC) and his son Alexander I of Macedon (r. 498 – 454 BC). The period of Achaemenid Macedonia came to an end in roughly 479 BC with the ultimate Greek victory against the second Persian invasion of Greece led by Xerxes I and the withdrawal of Persian forces from the European mainland.

During the age of Classical Greece, Perdiccas II of Macedon (r. 454 – 413 BC) became directly involved in the Peloponnesian War (431–404 BC) between Classical Athens and Sparta, shifting his alliance from one city-state to another while attempting to retain Macedonian control over the Chalcidice peninsula. His reign was also marked by conflict and temporary alliances with the Thracian ruler Sitalces of the Odrysian Kingdom. He eventually made peace with Athens, thus forming an alliance between the two that carried over into the reign of Archelaus I of Macedon (r. 413 – 399 BC). His reign brought peace, stability, and financial security to the Macedonian realm, yet his little-understood assassination (perhaps by a royal page) left the kingdom in peril and conflict. The turbulent reign of Amyntas III of Macedon (r. 393 – 370 BC) witnessed devastating invasions by both the Illyrian ruler Bardylis of the Dardani and the Chalcidian city-state of Olynthos, both of which were defeated with the aid of foreign powers, the city-states of Thessaly and Sparta, respectively. Alexander II (r. 370 – 368 BC) invaded Thessaly but failed to hold Larissa, which was captured by Pelopidas of Thebes, who made peace with Macedonia on condition that they surrender noble hostages, including the future king Philip II of Macedon (r. 359 – 336 BC).

The Odrysian kingdom (/oʊˈdrɪʒən/; Ancient Greek: Βασίλειον Ὀδρυσῶν), also known as Odrysia, was an ancient Thracian state that thrived between the early 5th century BC and the early 3rd / late 1st century BC. Located in present-day Bulgaria, southeastern Romania (Northern Dobruja), northern Greece and European Turkey, it was a tribal amalgam dominated by the Odrysians that was the first large political entity to develop in the eastern Balkans.

The Odrysian kingdom was founded by king Teres I, who was exploiting the collapse of the Persian presence in Europe due to the failed invasion of Greece in 480–79. Teres and his son Sitalces pursued a policy of expansion, making the kingdom one of the most powerful of its time. Throughout much of its early history it remained an ally of Athens and even joined the Peloponnesian War on its side. By 400 BC the state showed first signs of fatigue, although the skilled Cotys I initiated a brief renaissance that lasted until his murder in 360 BC.