scholars believe no such truce was concluded, and place Cimon's return from exile at a later date. Athenian success can also be attributed to them making an alliance with Argos, Sparta's enemy and only threat for control over the Peloponnesian league. The alliance between Athens and Argos was moreover seen as a defensive measure to counteract Sparta's military strength. Athens conquers The Athenians rebounded well after their defeat at Tanagra, by sending an army under Myronides to attack Boeotia. The Boeotian army gave battle to the Athenians at Oenophyta. The Athenians scored a crushing victory which led to the Athenians conquering all of Boeotia except for Thebes, as well as Phocis and Locris. The Athenians pulled down Tanagra's fortifications and took the hundred richest citizens of Locris and made them hostages. The Athenians also took this chance to complete the construction of their long walls. Shortly after this, Aegina surrendered and was forced to pull down its walls, surrender its fleet and became a tribute-paying member of the Delian League, completing what Donald Kagan has called an annus mirabilis for the Athenians.<ref name="Kagan95">Kagan, The Outbreak of the Peloponnesian War", 95</ref> The Athenians, pleased by their success, sent an expedition under the general Tolmides to ravage the coast of the Peloponnese. The Athenians circumnavigated the Peloponnese and attacked and sacked the Spartan dockyards, whose location was most probably Gythium. The Athenians followed up this success by capturing the city of Chalcis on the Corinthian Gulf and then landing in the territory of Sicyon and defeating the Sicyonians in battle. The importance of Megara Modern scholars have emphasised the critical significance of Athenian control of Megara in enabling the early Athenian successes in the war. Megara provided a convenient port on the Corinthian Gulf, to which Athenian rowers could be transported overland, and a significant number of ships were probably kept at Megara's port of Pagae throughout the war. Moreover, while early modern scholars were sceptical of Athens' ability to prevent a Spartan army from moving through the Megarid, recent scholarship has concluded that the pass of Geraneia could have been held by a relatively small force. Thus, with the isthmus of Corinth closed and Athenian fleets in both the Corinthian and Saronic gulfs, Attica was unassailable from the Peloponnese. The Spartans' inability to attack Megara proved to be a key component in their loss to the Athenians, but one scholar believes