In the summer of 425 BC, an Athenian fleet commanded by Eurymedon and
Sophocles, with
Demosthenes aboard as an advisor, sailed from Athens to campaign in
Sicily and assist Athens' democratic allies at
Corcyra. Demosthenes held no official position at the time, but was a
strategos-elect for the Hellenic year that would begin in midsummer 425, and the two generals had been instructed to allow him to use the fleet around the Peloponnese if he wished. Once the fleet was at sea, Demosthenes revealed his plan, which he had previously kept secret; he wished to land at and fortify Pylos, which he believed to be a particularly promising site for a forward outpost. (Pylos was a good distance from Sparta by march, and commanded an excellent harbour in the Bay of Navarino.). The generals rejected this plan, but Demosthenes caught a stroke of luck when a storm blew and drove the fleet to the shore at Pylos. Even then the generals refused to order the fortification of the promontory, and Demosthenes was similarly rebuffed when he attempted to appeal directly to the troops and subordinate commanders; only when the boredom of waiting out the storm overcame the Athenians did they set to work building fortifications. Once they began, however, the Athenians worked hard and quickly, and the promontory was fortified and defensible within a few days. The fleet sailed off towards
Corcyra, where a Spartan fleet of 60 ships was operating, leaving Demosthenes with five ships and their complements of sailors and soldiers to defend the new fort. The Spartan government was initially unconcerned with the Athenians' presence at Pylos, assuming that they would soon depart. Once it became clear, however, that Demosthenes and his men intended to hold the site, the
Eurypontid king of Sparta,
Agis, who was at the head of an army ravaging
Attica, turned for home, cutting his invasion short after only 15 days in Athenian territory. Once he reached home, Spartan forces immediately moved towards Pylos, the fleet at Corcyra was ordered to sail there immediately, and a summons was sent out calling allied states around the Peloponnese to send troops. The Spartan fleet managed to slip past the Athenian fleet at
Zacynthus, but Demosthenes anticipated its arrival and dispatched two of his triremes to inform the Athenian fleet of Pylos' plight; that fleet set out for Pylos as soon as it received the news. Pylos, meanwhile, had been reinforced by the arrival of a privateer with a cargo of arms, which were distributed to the sailors, and by a Messenian pinnace, which brought 40 more
hoplites to defend the peninsula. (Donald Kagan has asserted that these apparently fortuitous arrivals must have been the result of planning by Demosthenes.) To meet the imminent Spartan attack, Demosthenes divided his force, placing most of his men at the point where the promontory touched the mainland, while he with 60 hoplites and a few archers waited at the point facing out to sea where the Athenian wall was weakest. When the Spartan fleet arrived, the Spartans prepared to blockade the entrance to the harbour by placing hoplites on the island of
Sphacteria, which was in the middle of the entrance, and planned to place ships in the gaps on either side of that island when the Athenian fleet arrived. ==Battle==