The stare of the Byzantine Empire
No doubt that the restoration of 1261 significantly weakened Byzantine defensive power in Asia Minor. This weakened period of the Byzantine empire will be well used by the Turks. The Mongol invasion which shocked Europe caused mass migrations of Turkic Tribes towards Asia Minor and the Byzantine border. The Turks drowned Asia Minor without encountering any resistance except in major cities. By the year 1300 all of Asia Minor was under Turkish rule. In this Turkish storm only major fortresses like Nicaea, Nicomedia, Bursa, Sardis, Philadelphia, Magnesia survived. The conquered country was divided amongst the Turkic leaders. Thus, in western Asia Minor occurred several Turkish principalities. Old Bithynia was held by Osman, the father of the Ottoman dynasty, which later united under his scepter all Turkish tribes and Conquered Byzantium and South Slavic countries. Byzantium stood helpless and confused before the catastrophe that collapsed over her.
The Catalan Company
In this hopeless situation suddenly a shining new ray of hope. Roger de Flor, captain of the famous Catalan Company or officially known as Magna Societas Catalanorum, had offered to the emperor their services in the fight against the Turks. The Catalan Company helped the Sicilian king Frederik in his battle with the house of Anjou. After the peace of Caltabellotta, which ended the war in favor of the Aragonese dynasty left the Catalan mercenaries without jobs and seeking new service. The Byzantine Emperor accepted their service with great joy and in late 1303 Roger De Flor arrived in Constantinople with 6,500 soldiers. Placing all his hope in the Catalans, Andronicus II gave the agreed salary for four months in advance, engaged Roger de Flor to his niece Maria Asen, appointed him Megas Dux, and later even the title of Caesar.
The Catalan Company under the service of the Emperor
In early 1304 the Catalan company went to Asia Minor attacking the city of Philadelphia (Φιλαδέλφεια), which was under siege by the Turks. With a swift attack, they easily defeated the Turks. Roger de Flor entered the liberated city as a victor. This victory showed that a small but powerful army could change the outcome of the battle. The tragedy for the Byzantine Empire was that she had no longer an army like this and she had to hire foreign mercenaries. But the foreign mercenary army was a dangerous weapon, especially when it constituted an autonomous body and it could refuse to obey the weak government.
The death of Roger de Flor
After their victory the Catalan Company started to ravage the surrounding countries, robbing them, regardless if they were Turks or Byzantines and finally instead of fighting the Turks they invaded Byzantine Magnesia. The government in Constantinople was relieved that they managed to convince them to return. The Catalan Company spent the winter of 1304/5 in Gallipoli in preparation for another spring invasion of Asia Minor. However, tensions between the mercenaries and the Empire constantly increased. In Constantinople there was growing indignation against the boldness of the mercenaries, especially angry towards them was the heir to the throne Michael IX. Meanwhile the Catalan Company was embittered because they weren’t receiving their regular agreed salary and they used this as justification for their ravages and transgressions. The clash intensified to such an extent that in April 1305 Roger de Flor was killed in the Place of Michael IX. The Byzantines believed that with this they will get rid of the turbulent mercenaries when in fact the worst was yet to take place.
The Revenge of the Catalan Company
The Indignant Catalans took up arms in revenge for the death of their leader and now there was open war. In Trace during the battle of Apros the motley army of Michael IX suffered a heavy defeat and Michail IX himself was wounded and barely escaped with his life. For two years the Catalan company reinforced by fresh forces coming from the motherland and the recruitment of Turkish troops, ruthlessly ravaged and plundered throughout Thrace. After they ravaged all of Trace they went through the Rhodope Mountains and in the autumn of 1307 they settled in Kassandreia. From here they continued their looting everywhere, not sparing even the monasteries on Mount Athos, They even tried an attack on Thessalonica by land and sea but they failed to capture the City.
The Catalan Principality
In 1310 Roger Deslaur then offered the service of the Catalan Company to Walter V of Brienne Duke of Athens and within a year the experienced and unbeatable mercenaries freed the duchy of its enemies, only to be betrayed by Brienne, who refused to pay them their salaries. The Company once again avenged itself, defeating and killing Brienne in the Battle of Halmyros on 15 March 1311, taking control of the duchy of Athens and creating their own Catalan principality. Around this time, the Company also conquered the city of Thebes. In 1318 the Company expanded its power into Thessaly, taking control of the Duchy of Neopatria. The Catalan rule was to last until 1388–1390, when they were defeated by the Navarrese Company under Pedro de San Superano, Juan de Urtubia, and allied with the Florentines under Nerio I Acciaioli of Corinth. His descendants controlled them until 1456 when they were conquered by the Ottoman Empire. By that time, like many military enterprises, the Great Company had faded out of history.