Titus Livius (Livy), The History of Rome, Book 31
Cyrus Evans, Ed.

33. Meanwhile Philip was making vigorous preparations for carrying on the war both by sea and land. [2] His naval forces he drew together at Demetrias in Thessaly; supposing that Attalus, and the Roman fleet, would move from Aegina [p. 1375]in the beginning of the spring. [3] He gave the command of the fleet and of the sea-coast to Heraclides, to whom he had formerly intrusted it. The equipment of the land forces he took care of in person; considering that he had deprived the Romans of two powerful auxiliaries, the Aetolians on the one side, and the Dardanians on the other, by making his son Perseus block up the pass at Pelagonia. [4] The consul was employed, not in preparations, but in the operations of war. He led his army through the country of the Dassaretians, conveying the corn untouched which he had brought from his winter quarters, for the fields afforded supplies sufficient for the consumption of the troops. [5] The towns and villages surrendered to him, some through inclination, others through fear; some were taken by assault, others were found deserted, the barbarians flying to the neighbouring mountains. [6] He fixed a standing camp at Lycus near the river Bevus, and from thence sent to bring in corn from the magazines of the Dassaretians. Philip saw the whole country filled with consternation, and not knowing the designs of the consul, he sent a party of horse to discover whither he was directing his course. [7] The same state of uncertainty possessed the consul; he knew that the king had moved from his winter quarters, but in what direction he had proceeded he knew not: he also had sent horsemen to gain intelligence. [8] These two parties, having set out from opposite quarters, after wandering a long time among the Dassaretians, through unknown roads, fell at length into the same track. Neither doubted, as soon as the noise of men and horses was heard at a distance, that the enemy was approaching, therefore, before they came within sight of each other, they got their arms in readiness, nor, when they saw their foe, was there any delay in engaging. [9] As they happened to be nearly equal in number and valour, being picked men on both sides, they fought during several hours with vigour, until fatigue, both of men and horses, put an end to the fight, without deciding the victory. Of the Macedonians there fell forty horsemen; of the Romans thirty-five. [10] Still, however, neither did the one party carry back to the king, nor the other to the consul, any certain information in what quarter the camp of his enemy lay. [11] But this was soon made known to them by deserters, whom their [p. 1376]recklessness of disposition supplies in all wars in sufficient number to discover the affairs of the contending parties.