It was essential for Thebes to reopen communication with her Peloponnesian allies. Accordingly Epaminondas, at the head of the Thebans and their northern allies, arrived during the same summer in front of this position, on his march into Peloponnesus. His numbers were inferior to those of his assembled enemies, whose position prevented him from joining his Arcadian, Argeian, and Eleian allies, already assembled in Peloponnesus. After having vainly challenged the enemy to come down and fight in the plain, Epaminondas laid his plan for attacking the position. Moving from his camp a little before daybreak, so as to reach the enemy just when the night-guards were retiring, but before the general body had yet risen and got under arms,[546]—he directed an assault along the whole line. But his principal effort, at the head of the chosen Theban troops, was made against the Lacedæmonians and Pellenians, who were posted in the most assailable part of the line.[547] So skilfully was his movement conducted, that he completely succeeded in surprising them. The Lacedæmonian polemarch, taken unprepared, was driven from his position, and forced to retire to another point of the hilly ground. He presently sent to solicit a truce for burying his dead; agreeing to abandon the line of Oneium, which had now become indefensible. The other parts of the Theban army made no impression by their attack, nor were they probably intended to do more than occupy attention, while Epaminondas himself vigorously assailed the weak point of the position. Yet Xenophon censures the Lacedæmonian polemarch as faint-hearted, for having evacuated the whole line as soon as his own position was forced; alleging, that he might easily have found another good position on one of the neighboring eminences, and might have summoned reinforcements from his allies,—and that the Thebans, in spite of their partial success, were so embarrassed how to descend on the Peloponnesian side of Oneium, that they were half disposed to retreat. The criticism of Xenophon indicates doubtless an unfavorable judgment pronounced by many persons in the army; the justice of which we are not in a condition to appreciate. But whether the Lacedæmonian commander was to blame or not, Epaminondas, by his skilful and victorious attack upon this strong position, enhanced his already high military renown.[548] [546] Xen. Hellen. vii, 1, 16; Polyænus, ii, 2, 9. This was an hour known to be favorable to sudden assailants, affording a considerable chance that the enemy might be off their guard. It was at the same hour that the Athenian Thrasybulus surprised the troops of the Thirty, near Phylê in Attica (Xen. Hellen. ii, 4, 6). [547] Xen. Hellen. ib.; Pausanias, ix, 15, 2. Pausanias describes the battle as having been fought περὶ Λέχαιον; not very exact, topographically, since it was on the other side of Corinth, between Corinth and Kenchreæ.