Titus Livius (Livy), The History of Rome, Book 27
Frank Gardner Moore, Professor Emeritus in Columbia University, Ed.

31. While the king was engaged in preparing for the games and relaxing during the festal days with more freedom than in war-times, Publius Sulpicius sailing from Naupactus put in with his fleet between Sicyon and Corinth and ravaged a region of the most noted fertility far and wide. [2] The report of this called Philip away from the games; and setting out in haste with the cavalry, after ordering the infantry to follow, he attacked the Romans, who, fearing nothing of the kind, were widely scattered over the country and loaded down with their plunder, and he drove them to their ships. [3] The Roman fleet, not at all happy over its plunder, returned to Naupactus. For Philip the remainder of the games also had gained in festivity from the news of a victory, unimportant as it might be, but still over the Romans. [4] And the festival was observed with immense rejoicing, all the more because, to be popular, he had removed his diadem and purple and other regal attire, and in appearance had put himself on the same plane as the others, than which nothing is more acceptable to free states. [5] Also by doing so he would have offered them no uncertain hope of freedom, had he not degraded and debased everything by his insufferable lust. For with one or two companions he would roam day and night round the homes of married couples, and lowering himself to the level of a private citizen, the less he was observed the more unrestrained was he; [6] and liberty, of which [p. 339]he had made but an empty show to others, for his¹ purpose he had turned wholly to licence. [7] For he did not obtain everything by purchase or cajoling, but even employed force to gain his shameful ends. And it was dangerous for both husbands and parents if they had delayed the royal lust by disobliging strictness. [8] Even from Aratus, one of the leading men of the Achaeans, his wife, named Polycratia, had been taken away and carried off into Macedonia with the prospect of a royal marriage.

[9] After the festival of the Nemea had been completed in the midst of such shameful conduct, and he had added a few more days, he set out for Dymae, in order to expel the Aetolian garrison which had been summoned by the Eleans and admitted to their city.² [10] Cycliadas, who held the chief command, and the Achaeans met the king near Dymae, being not only inflamed with hatred of the Eleans because they were at odds with the rest of the Achaeans, but also hostile to the Aetolians, who, they believed, had stirred the Romans likewise to a war against them. [11] Setting forth from Dymae and uniting their armies, they crossed the river Larisus, which separates the Elean territory from that of Dymae.