Tithorea was the operational center of Onomarhos, born near Tithorea in the settlement of Parapotamioi, Emperor of the Phocians, the most powerful personality of Greece from 353 BC to 352 BC, where at that time it had occupied Thronio in Locri, subjugated Amfissa, conquered Doric Tetrapolis and Orchomenos. The Phocians King Onomarchos, led the entire Phocian army and invaded Thessaly twice (354-353 BC), where after an equal number of victories forced Philip to return to Macedonia, but Onomarchos in the third match, with the Macedonians had a fatal end to the battle that took place at Krokion Field near the Pagasitic Gulf, where the Phocian forces were defeated and the Onomarchos killed during the battle. Philip, in retaliation for the defeats suffered by the Phocians in 338 BC, conquered and leveled the Phocian cities.
Tithorea was the operational center of Onomarhos, ruled by Emperor Onomarchos, who led the Phocian army to invade Thessaly twice, forcing Philip to retreat. The battle at Krokion Field near the Pagasitic Gulf resulted in a defeat for the Phocians and Onomarchos' death, leading to retaliation by Philip who conquered and destroyed Phocian cities.