Battle of Halmyros

Battle of Halmyros
Map of the Greek and Latin states in southern Greece c. 1278
Date 15 March 1311 Location Halmyros, southern Thessaly (or by the Boeotic Cephissus, near Orchomenos) 39°10.8′N 22°45.6′E / 39.1800°N 22.7600°E / 39.1800; 22.7600 Result Catalan victory and conquest of the Duchy of Athens
Belligerents
Catalan Company	Duchy of Athens and allies
Commanders and leaders
Unknown	Walter V †
Strength
2,000 cavalry 4,000 infantry (Chronicle of the Morea) 3,500 cavalry 4,000 infantry (Gregoras)	700 knights 24,000 infantry (Muntaner) 6,400 cavalry 8,000 infantry (Gregoras) 2,000 cavalry 4,000 infantry (Chronicle of the Morea)
Casualties and losses
Unknown	Very heavy
class=notpageimage| Location within Greece

The Battle of Halmyros, known by earlier scholars as the Battle of the Cephissus or Battle of Orchomenos,^[1] was fought on 15 March 1311, between the forces of the Frankish Duchy of Athens and its vassals under Walter of Brienne against the mercenaries of the Catalan Company, resulting in a decisive victory for the mercenaries.

Engaged in conflict with their original employers, the Byzantine Empire, the Catalan Company had traversed the southern Balkans and arrived in southern Greece in 1309. The new Duke of Athens, Walter of Brienne, hired them to attack the Greek ruler of neighbouring Thessaly. Although the Catalans conquered much of the region for him, Walter refused to pay them and prepared to forcibly expel them from their gains. The two armies met at Halmyros in southern Thessaly (or at the Boeotic Cephissus, near Orchomenos, according to an earlier interpretation). On the Athenian side, many of the most important lords of Frankish Greece were present. The Catalans were considerably outnumbered and weakened by the reluctance of their Turkish auxiliaries to fight. They did have the advantage of selecting the battleground, positioning themselves behind marshy terrain, which they further inundated. Walter, a prideful man and confident in the prowess of his heavy cavalry, charged headlong against the Catalan line. The marsh impeded the Frankish attack and the Catalan infantry stood firm. The Turks re-joined the Company and the Frankish army was routed, with Walter and almost the entire knighthood of his realm falling in the field. Subsequently the Catalans took over the leaderless Duchy of Athens, ruling that part of Greece until the 1380s.