Battle of the Cephissus

The Battle of the Cephissus, also known as the Battle of Halmyros or Orchomenos, was fought on 15 March 1311 between the Frankish Greek forces of Walter V of Brienne and the mercenaries of the Catalan Company, resulting in a devastating victory for the Catalans.

Background
Walter V had hired the Company to defend his Duchy of Athens from the neighboring Greek states the Despotate of Epirus, the Byzantine Empire, and the Vlach-inhabited entity called Great Wallachia. This they did with great success, but Walter attempted to discharge them, picking a moiety of the company and paying them lavishly to remain in his service, while ordering the expulsion of the rest without their pay. When the Company resisted, Walter assembled the feudal host of Frankish Greece, with reinforcements sent from Naples, assembling 700 Frankish knights and native Greek horsemen, a large number of infantry, mostly native Greeks (set at 24,000 by Muntaner), as well as the 200 horsemen and 300 footmen he had selected from the Catalan Company.

Battle
The Company assumed a defensive position on the plain of Orchomenus, near the River Cephissus. Their Turkish auxiliaries took up a separate position nearby, thinking the quarrel was a pretext arranged by the Company and the Duke of Athens to exterminate them. To protect their position, the Catalans broke dikes and dug trenches, diverting water from the Cephissus to flood the fields lying in front of them.

On the eve of battle, the Catalans in the Duke's service, stricken by conscience, took leave of him and rejoined the Company. This circumstance little disturbed the Duke, who still outnumbered the company, and had at his command the chivalry of the Frankish states in Greece, considered the flower of the French-speaking world. The Duke, with his banner in the vanguard, opened the battle with a cavalry charge against the Catalans, followed by the infantry. In the morass covering the Catalan front, the cavalry soon became hopelessly mired, the Duke and his banner falling in a rain of javelins from the almogàvers. As the lightly equipped Catalans advanced to cut down the wallowing knights, the Turkish auxiliaries descended from their camp upon the Athenian army, panicking and routing what remained of it.

According to Muntaner, only two of the seven hundred knights survived the battle, Roger Deslaur and Boniface of Verona. However, Nicholas Sanudo, later Duke of the Archipelago, also escaped, and a few others, like Antoine le Flamenc, were probably ransomed. Muntaner claims that 20,000 of the infantry were killed, and all of the native horse.

Aftermath
The battle is sometimes compared to the Battle of Agincourt where light, missile-armed troops were able to defeat heavily encumbered opponents hindered by adverse terrain. The paralyzing charge into the bogs and the slaughter that followed resulted in the near annihilation of the nobility of the Principality of Achaea and its vassal states. The Catalan Company proceeded to occupy the Duchy of Athens, which they placed under the protection of a prince of the House of Aragon and ruled until 1379. This tremendous smash also ended the golden age of Frankish chivalry in the Duchy of Athens. The remaining Latin states would now be largely dependent on external powers such as Naples and Venice for support.

Primary

 * The Chronicle of Ramon Muntaner, translated into English by Lady Goodenough