The site is first mentioned in 813 as "Akedoukton" or "ta Kidoktou", when Michael I Rhangabe campaigned against the Bulgars, and was escorted by his wife Prokopia. Her presence was unwelcome to the troops, who rioted. In October or November 822, the plain was the site of the decisive battle in the rebellion of Thomas the Slav, between the rebel forces and the Bulgars under Omurtag, who was allied to Emperor Michael II the Amorian. The battle was costly for both sides and resulted in no clear winner, but weakened Thomas, leading to the collapse of his rebellion in spring 823.