The Almogavars came originally from the Pyrenees, and were in later times recruited mainly in Navarre, Aragon, and Catalonia. They were frontiersmen and foot-soldiers who wore no armour, dressed in skins, were shod with brogues (abarcas), and carried the arms similar to those of Roman legionaries: two heavy javelins, or "assegai" (atzagaia in Catalan);and a short stabbing sword.
They were professional soldiers, and served kings, the Roman Catholic Church, nobles, or towns for pay; eventually they also hired themselves out to the Byzantine Empire. When Peter III of Aragon made war on Charles of Anjou after the Sicilian Vespers of March 30 1282 for the possession of Naples and Sicily, the Almogavars formed the most effective element of his army. Their discipline and ferocity, the force with which they hurled their javelins, and their activity, made them very formidable to the heavy cavalry of the Angevin armies. They fought against cavalry by attacking firstly horses instead of knights. Once the knight was on the ground he was an easy victim for the Almogavar.
When the Peace of Caltabellotta in 1302 ended the war in southern Italy, the Almogavars, under the leadership of Roger de Flor ("Roger Blum", a former Knight Templar), formed the Catalan Company in the service of the emperor of the East, Andronicus II Palaeologus, to fight against the Turks. Both kings of Aragon and Sicily agreed with the idea since peace had been reached and it was viable alternative to having the Almogavar standing army unemployed in their realms.
Their campaign in Asia Minor during 1303 and 1304 was a series of military victories, but when they insisted in receiving the agreed payment, the Emperor refused. Thereafter the Almogavars turned to violence, making their presence intolerable to the Byzantine population. Roger de Flor and his lieutenants were assassinated by orders of the Emperor 1305 while meeting to discuss terms on their compensation, presumably on the instigation of Genoese merchants, who were conspiring to keep their own position of influence and power and keep the Catalans out of the loop. This betrayal resulted in the Almogavars ravaging the neighbourhood of Constantinople.
Subsequently they marched against the Duchy of Athens, under the rule of the French House of Brienne. Duke Walter V of Brienne was defeated and slain by the Almogavars with all his knights at the Battle of the Cephissus, or Orchomenus, in Boeotia in March 1310. They then divided the wives and possessions of the Frenchmen by lot, and summoned a prince of the house of Aragon to rule over them.
The foundation of the Aragonese rule over the duchy of Athens was to be the culminating achievement of the Almogavars. Although the duchy eventually fell to the Ottoman Empire, even today the King of Spain still holds the title of 'Duke of Athens and Neopatria'.
The name "Almogavars" was revived for a short time as a party nickname in the civil wars during the reign of Ferdinand VII of Spain. The parachute brigade of the modern-day Spanish army is also named Brigada de Infantería Ligera Paracaidista Almogávares VI (Parachute Light Infantry Brigade "Almogavars" VI).
This article is mainly based on an entry in the 1911 Encyclopedia Britannica.