This ruler was attacked in a series of letters written by his secretary Megaleas, who committed suicide rather than stand trial for treason.
This ruler was attacked in a series of letters written by his secretary Megaleas, who committed suicide rather than stand trial for treason. This king's conquests were recognized by the Peace of Phoenice, after a war in which he sacked the city of Thermo and stole its treasure. He solidified his rule by concluding the Peace of Naupactus to end the Second Social War. To clear an indemnity of a thousand silver talents and free his son from captivity, he joined the war against King Nabis. This ruler, who was frequently allied against by the Aetolian League, had his army destroyed in battle by an uphill charge of elephants led by T. Quinctius Flamininus. His son Perseus was later defeated at the Battle of Pydna, echoing this man's own failure at the Battle of Cynoscephalae. For 10 points, name this ruler known as "the beloved of all Greece," who for a time allied with Hannibal, and served as king of Macedon for over 40 years starting in 221 BC. 
This ruler was attacked in a series of letters written by his secretary Megaleas, who committed suicide rather than stand trial for treason.
Philip V of Macedon [prompt on Philip]