 This betrayal resulted in the surviving Almogavars, who resisted for two years a siege in Gallipoli and concentrated on the region of Thrace, leading off the Catalan Revenge, a war of extermination and systematic looting against the civilian population of the Byzantine Empire between 1305 and 1307 in revenge and retaliation for the murder of Roger de Flor and the attempted annihilation of the Company while it was stationed at Gallipoli.After a period of internal conflict, the Great Company left the line and moved to Greece where it was hired by the Duke of Athens, who didn't pay what they agreed to; so the Almogavars marched against the Duchy of Athens, under the rule of the French House of Brienne.In March 1310, Duke Walter V of Brienne and all his knights were defeated and slain by the Almogavars at the Battle of the Cephissus, or Orchomenus in Boeotia.