The 480s BCE in Athens are a period of intense political struggle.

Miltiades had died in disgrace and from 487 BCE to 483 BCE other leaders are successively ostracized.

Though never himself defeated, Themistocles is doubtless attacked repeatedly; he is the man accused by his enemies of being a danger to the established order.

Nonetheless, in 483 BCE he wins his greatest triumph.

The state-owned silver mines at Laurium, worked since Mycenaean times, are the site of a rich strike, and he persuades the assembly, instead of “declaring a dividend,” to devote the whole surplus to increasing the navy.

Thus when Xerxes I, the Persian king, finally marches against the Greeks in 480 BCE, Athens is to have two hundred triremes, though many of the rowers will still be untrained.

Themistocles further succeeds in selling his naval strategy to the Peloponnesians, headed by Sparta, who can raise another one hundred and fifty triremes.

The combined fleet is to fight not on their own doorstep, as Greeks prefer to do, but as far forward as possible, exploiting the geographical situation.

Gelo, recruiting mercenaries widely, builds up a strong fleet and conquers the nearby Ionian Greek cities of Euboea and …

…Megara Hyblaea in about 483 BCE, selling their common people into slavery and bringing their oligarchs to Syracuse.

He controls the Greek and Sicel communities of east Sicily and becomes linked by marriage with Theron, tyrant of Akragas (later the Roman Agrigentum, modern Agrigento).

The city of Himera had once requested Phalaris, tyrant of Akragas (570-554 BCE), to rule them.

Theron in 483 BCE emulates Phalaris when he deposes Terillus and adds Himera to his domain.

Terillos had come to power in Himera after expelling the ruling oligarchs (who had taken refuge in Akragas), and he probably lacks popular support, which may have been exploited by Theron.

Terillos requests the aid of Hamilcar, Suffet of Carthage.

Anaxilas also lobbies on his behalf, and sends his own children as hostages to Carthage as a token of loyalty.

Akragas, another Doric city, has meanwhile taken over neighboring Sican and Sicel lands under the tyrant Theron.

To forestall any conflicts between Akragas and Syracuse, Gelo and Theron have married into each other’s families, thus creating a united front against the Sicels and Ionian Greeks of Sicily.

Selinus, a Doric city whose territory borders Theron's domain, also becomes a Carthaginian ally—perhaps the fear of Theron and the destruction of Megara (mother city of Selinus) by Gelo, had played a part in this decision.

Thus, three power blocks are delicately balanced in Sicily by 483 BCE—Ionians dominating the north, Carthage the west, Dorians the east and south.

The Sicels and Sicans in the interior remain passive, and if not directly under Greek rule, do not hinder the movements of their forces.

The Elymians join the Carthaginian alliance.

Xerxes had outraged the Babylonians in 484 BCE by violently confiscating and melting down the golden statue of Bel (Marduk, Merodach), the hands of which the rightful king of Babylon had to clasp each New Year's Day.

This sacrilege had led the Babylonians to rebel in 484 and 482 BCE, so that in contemporary Babylonian documents, Xerxes refuses his father's title of King of Babylon, being named rather as King of Persia and Media, Great King, King of Kings (Shahanshah) and King of Nations (i.e.

of the world).

Xerxes deals with the revolt by razing the walls and plundering the city.

Aristides is ostracized and banned from Athens in 482 BCE, probably because he opposes Themistocles' plan to finance the building of a large fleet by using the silver from the new vein.

Darius’ death has left to his son the task of punishing the Athenians, Naxians, and Eretrians for their interference in the Ionian Revolt, the burning of Sardis and their victory over the Persians at Marathon.

From 483 BCE, Xerxes had begun preparing his expedition: A channel is dug through the isthmus of the peninsula of Mount Athos, provisions are stored in the stations on the road through Thrace, two pontoon bridges later known as Xerxes' Pontoon Bridges are built across the Hellespont.

Soldiers of many nationalities serve in the armies of Xerxes, including the Assyrians, Phoenicians, Babylonians, Egyptians and Judahites.

Among the Phoenician naval contingents of the Persian fleet are the sailors of Sidon.

Xerxes concludes an alliance with Carthage, and thus deprives Greece of the support of the powerful monarchs of Syracuse and Akragas.

Many smaller Greek states, moreover, take the side of the Persians, especially Thessaly, Thebes and Argos.

The Second Persian War is a very different proposition from the first.

Xerxes in 481 BCE uses a bridge of boats to cross the Hellespont at Abydos with a huge fleet and an army of over one hundred thousand troops. (Herodotus estimates the Persian army to number in the millions, but modern scholars tend to doubt his figures, replacing them with far lower ones.)

The unprecedented size of Xerxes' forces makes their progress quite slow, giving the Greeks plenty of time to prepare their defense.