Battle of Petroe
1057 CE.
Shown on the map at 40.487°, 29.691°.
The Battle of Petroe, also known as the Battle of Hades, was fought on 20 August 1057 between two rival Byzantine armies: the loyalist forces of the Byzantine emperor Michael VI Stratiotikos (r. 1056–1057) under the proedros Theodore, and the supporters of the rebel general Isaac Komnenos. Disgruntled by the neglect of army finances and the Emperor's unwillingness to consider their grievances, Komnenos and other leading commanders, including Nikephoros Bryennios and Nikephoros Botaneiates, began plotting against Michael VI, and on 8 June 1057, Komnenos was proclaimed emperor at his estates in Cappadocia. After his supporters rallied regiments from Anatolia to his cause, his army marched west towards Constantinople, and encountered the loyalist army, composed largely of regiments from Europe, near the city of Nicaea. After confronting each other for several days, the two armies finally engaged at the plain of Hades. Although the right wing of the rebel army was beaten, Komnenos himself held firm in the centre.
Text from the Wikipedia article Battle of Petroe, licensed CC BY-SA 4.0.