As the Spartans vainly endeavor in 462…

…he himself leads four thousand hoplites to Mount Ithome.

However, after an attempt to storm the place fails, the Spartans begin to wonder if they can trust the Athenians not to take the helot side and, retaining their other allies, dismisses Cimon and his contingent on suspicion of “revolutionary tendencies.”

Sparta’s insulting rebuff of Cimon, on the heels of the Spartans' “secret” promise to Thasos, causes the immediate collapse of his popularity at Athens: 461 at the next opportunity an ostracism, or vote for the exile of the most unpopular citizen, is held; Cimon heads the poll and has to leave Athens for ten years.

Outrage over Spartan dismissal has swung Athenian opinion in Ephialtes' favor, so that he is able in 462/461 to carry measures stripping the aristocratic court, the Areopagus, of its political power and to establish the dominance of the Ecclesia (the Popular Assembly), the Boule (Council), and law courts.

Opposition to these measures results in the assassination of Ephialtes, but his political revolution is consolidated.

The preponderant power of Athens has made the Delian league subservient to Athenian interests, speeded by the willingness of the allies to contribute money instead of ships, for Athens' fleet grows larger as those of the allies grow smaller.

Athens sets the level of tribute for the member states, which are now subject to its dictates, and it deals harshly with failures to pay.

Athens also begins regulating the internal policy of the other states and occasionally garrisoning soldiers there.

League policy enters a new phase as relations between Athens and Sparta break down in 461.

Athens reacts by allying itself with …

…Argos and …

…Thessaly, which is a blow to Spartan ambitions both in its obvious stronghold, the Peloponnese, and in central Greece, an area into which one group of Spartans always seems to have wanted to expand.

Inarus, the son of a Libyan prince named Psamtik, presumably of the old Saite line, holds a kingship over the Libyans from Mareia (above Pharos) and the part of the Nile Delta around Sais.

With help from Amyrtaeus, also from Sais, who takes the northern marshes, Inarus drives out the tax-collectors and collects mercenaries, thus starting a revolt in Egypt during the reign of King Artaxerxes I of Persia after the assassination of King Xerxes I.

The Athenians take the ambitious decision to support the revolt in the Egyptian satrapy of the Persian empire, forming an alliance with the Egyptian leader Inaros against the Persians towards the end of the 460s BCE.

In order to reach the Nile delta and support the Egyptians, the Athenian fleet has to sail south.

Athens has secure landing sites for their triremes as far south as Cyprus but they need a way station between Cyprus and Egypt.

Ideally, they require a naval base on the coast of Lebanon or Palestine but the Phoenician cities of Sidon and Tyre hold much of the mainland coast and those cities are loyal to Persia.

Fifty miles south of those cities, however, the Athenians find an isolated and tempting target for establishing a way station.

Dor has many strategic advantages for the Athenians, starting with its distance from Sidon.

The Athenians have a maritime empire built on oared ships.

They do not need large tracts of land and instead need strategically situated coastal sites that haves fresh water, provisions and protection from bad weather and enemy attack.

Dor has an unfailing freshwater spring near the edge of the sea and to its south a lagoon and sandy beach enclosed by a chain of islets.

This is precisely what the Athenian fleet requires for landing their ships and resting their crews.

Dor itself is strategically situated.

Standing atop a rocky promontory, it is protected on its landward side by a marshy swale that forms a natural moat.

Beyond the coastal lowlands is Mount Carmel.

The town has Persian-built fortifications.

In addition to this, the town has straight streets and Phoenician dye pits for the purpling of cloth.

For these reasons, Dor, which the Athenians seize from Sidon in 460 BCE, becomes the most remote outpost of the Athenian navy.

Themistocles, who has issued some coins, in the past few years, allegedly commits suicide in about 460 when called upon by his Persian hosts to take part in a naval war against the Athenians.

The Athenian allies, from whom Inarus is paid one hundred triers, send troops and an army of more than two hundred ships led by Charitimides to aid him in 460 BCE.

The Messenian defenders of Mount Ithome leave the Peloponnese in about 460 BCE.

Corinth as far as is known had made no move to help Sparta at the time of the Ithome disaster but seems to have pursued expansionist goals of its own in the Peloponnese, perhaps at Argos' expense.

Now that Athens and Argos are allied, this indirectly tends to damage Corinth's hitherto good relations with Athens. (Corinth had fought well at Salamis, as even Herodotus was aware, although after 460 very different stories were circulating on this topic.)

More relevant than this is Athens' ready reception of a third ally, Megara; …