The success of the Athenian negotiations appears not to have been so great in Peloponnesus as in the northern states, though these were exposed to the enemy’s first attacks. Sparta, Arcadia, and Achaia kept aloof from the struggle to the end—whether restrained by jealousy of Athens, or by the remembrance of the last unfortunate contest with Macedonia. Messene, Elis, Sicyon, Phlius, Epidaurus, Trœzen, and Argos joined the confederacy; but even of these, several appear to have held back until they were encouraged by the first success of the other allies. In northern Greece, Leosthenes himself was one of the most active and successful envoys. As soon as he had completed the equipment of his levies at Tænarus, leaving them, it seems, under the command of an inferior officer, he went over to Ætolia. He found the Ætolians, who had been alarmed and incensed by Alexander’s threats about Œniadæ, heartily inclined to the national cause, and obtained a promise of seven thousand men. He then proceeded to solicit aid from Locris, Phocis, and others of the neighbouring states. Almost everywhere, from the borders of Macedonia to Attica, a good spirit prevailed. The Dolopians, the mountaineers of Œta, all the towns of Doris, Carystus in Eubœa, the Locrians and Phocians, many of the tribes in the western valleys of Pindus, as the Ænianians, Alyzæans, and Athamantians, the Leucadians, and a part at least, it seems, of the Acarnanians, sent their contingents. Even from beyond the borders of Greece, the allies received some auxiliaries: from the Molossian chief, Aryptæus, who, however, afterwards deserted and betrayed them, and in very small number from Illyria and Thrace. But the policy by which Thebes had been destroyed, and its territory divided among the Bœotian towns, was now attended with an effect more disastrous to Greece than the conqueror could have foreseen. It was known that the success of the Greeks would be followed by the restoration of Thebes—the Theban exiles probably formed a strong body in the Greek army; and hence the Bœotians, though surrounded on all sides by the forces of the confederacy, zealously adhered to the Macedonian cause, which was that of their private interest, and their inveterate hatred to the fallen city.
Antipater received the tidings of Alexander’s death—to him no mournful event—nearly at the same time with those of the movements in Greece. His situation was one of great difficulty and danger. The whole force immediately at his disposal was small, and, if he marched against Greece, it would be necessary to leave a part of it for the protection of Macedonia. Nevertheless Antipater determined not to wait for reinforcements nor to remain on the defensive, but to seek the enemy. The force which he was able to bring into the field amounted to no more than thirteen thousand foot, and six hundred horse. It might seem that he, rather than the Athenians, was acting rashly, when, with so small an army, he ventured to invade Greece: and perhaps he relied somewhat too confidently on the superiority of the Macedonian discipline and tactics, and on the recollection of his victory over Agis. It must however be observed, that he calculated on the support of the Thessalians, and probably of some other northern states; and he might hope by a rapid movement to crush the confederacy, before it had collected its forces, or at least to prevent it from receiving fresh accessions of strength. He had also ordered Sippas, whom he left to supply his place in Macedonia, to levy troops with the utmost diligence, and may have expected to be speedily reinforced by these recruits. His coffers were well filled, for he had received a large supply of treasure from Alexander; and the fleet which had brought it over, consisting of 110 galleys, remained with him, and was now ordered to attend the operations of the army.
Leosthenes was elected commander-in-chief, not more in honour of Athens than on account of the confidence which was reposed in his abilities. The Athenians could spare no more than five thousand infantry, and five hundred cavalry, of Attic troops; to these they added two thousand mercenaries. But now the Bœotians, encouraged perhaps by the tidings of Antipater’s approach, collected their forces to oppose the passage of this little army, and encamped near Platæa, no doubt in very superior numbers, to watch the passes of Cithæron. Leosthenes, apprised of their movement, hastened with a division of his troops to the relief of his countrymen, effected a junction with them, and gave battle to the enemy. He gained a complete victory, raised a trophy, and returned, with this happy omen of more important success, to his camp.