Upon learning of this compact between the league and Antigonus, Cleomenes raised the siege of Sicyon and pitched his camp near the Isthmus; and, having thrown up a line of fortification uniting the Acrocorinthus with the mountain called the “Ass’s Back,” began from this time to expect with confidence the empire of the Peloponnese. But Antigonus had made his preparations long in advance, in accordance with the suggestion of Aratus, and was only waiting for the right moment to act. And now the news which he received convinced him that the entrance of Cleomenes into Thessaly, at the head of an army, was only a question of a very few days: he accordingly despatched envoys to Aratus and the league to conclude the terms of the treaty[162] and marched to the Isthmus with his army by way of Euboea. He took this route because the Aetolians, after trying other expedients for preventing Antigonus bringing this aid, now forbade his marching south of Thermopylae with an army, threatening that, if he did, they would offer armed opposition to his passage. +53.+ Thus Antigonus and Cleomenes were encamped face to face: the former desirous of effecting an entrance into the Peloponnese, Cleomenes determined to prevent him. [Sidenote: The Achaeans seize Argos.] Meanwhile the Achaeans, in spite of their severe disasters, did not abandon their purpose or give up all hopes of retrieving their fortunes. They gave Aristotle of Argos assistance when he headed a rising against the Cleomenic faction; and, under the command of Timoxenus the Strategus, surprised and seized Argos. And this must be regarded as the chief cause of the improvement which took place in their fortunes; for this reverse checked the ardour of Cleomenes and damped the courage of his soldiers in advance, as was clearly shown by what took place afterwards. For though Cleomenes had already possession of more advantageous posts, and was in the enjoyment of more abundant supplies than Antigonus, and was at the same time inspired with superior courage and ambition: yet, as soon as he was informed that Argos was in the hands of the Achaeans, he at once drew back, abandoned all these advantages, and retreated from the Isthmus with every appearance of precipitation, in terror of being completely surrounded by his enemies. At first he retired upon Argos, and for a time made some attempt to regain the town. But the Achaeans offered a gallant resistance; and the Argives themselves were stirred up to do the same by remorse for having admitted him before: and so, having failed in this attempt also, he marched back to Sparta by way of Mantinea. [Sidenote: Antigonus receives the Acrocorinthus.]