The Bulgarian tsar now turns to Constantinople, which had inspired the Tatar invasions and has managed to conquer many Bulgarian fortresses in Thrace.

As a consequence of his victories, Theodore Svetoslav feels secure enough to move on to the offensive by 1303 and capture the fortresses of northeastern Thrace, including Mesembria (Nesebăr), …

Roger de Flor attends a banquet offered by Emperor Andronikos' son Michael XI Palaeologus in the imperial palace at Adrianople on April 30, 1305.

Here, Michael arranges Flor’s assassination, along with three hundred cavalry and one thousand infantry, by Alan mercenaries at the service of the emperor.

The surviving Catalans, outraged by the murder of their leader and their fellow mercenaries, take their vengeance on the empire by pillaging and murdering throughout imperial territories, especially in Thrace and Macedonia.

The emperor attacks Gallipoli in an attempt to conquer the city from the remnants of the Company under the command of Berenguer de Entença, who had arrived with nione Catalan galleys.

The attack is unsuccessful, but it largely decimates the Company.

(Entença will be captured by the Genoese shortly after, and later liberated.)

The Catalan Company has remaining only two hundred and six horsemen, twelve hundred and fifty-six foot soldiers, and no clear leader when emperor Michael attacks, , trusting in his numerical superiority, only to be defeated in Apros, in Thrace, in July 1305.

The treachery of the emperor has unleashed what is to become known as the Catalan Revenge against the Empire.

Following the rules of chivalry, they challenge the Emperor himself, whose only answer is to kill their embassies, and to order the massacre of all Catalan and Aragonese living in Constantinople.

The Company’s answer will be he devastation of the regions of Thrace and Macedonia for the next two years.

The leaderless Catalans, more inclined to pillage Greek cities than to fight the Turks, have taken to pillaging and murdering throughout imperial territories, especially in Thrace and Macedonia.

For some years, they have used the Gallipoli Peninsula as a base from which to ravage Thrace, inviting thousands of Turks to come over and help them.

The Company is a powerful asset in the political arena and Frederick III of Sicily tries to gain control over it, assigning the Infante Ferdinand of Majorca to Gallipoli to become its Captain.

However one of the leaders of the Company, Bernat de Rocafort, opposes this move, and faces Berenguer de Entença, Ferran Ximenis d'Arenós, and others who had accepted the Infante.

The struggle ends with the departure of the Infante and Ferran and with Rocafort becoming leader of the Company.

(The administrator, Ramon Muntaner also departs; he will later chronicle the Company’s exploits.)

Rocafort offers the Company's services to Charles of Valois, to strengthen his claim to the Empire.

The Catalans finally move west in about 1308.

The Catalan Company has freed the duchy of its enemies within a year, only to be betrayed by Brienne, who refuses to pay for is services.

The Company avenges itself on March 15, 1311, defeating and killing Brienne in the Battle of Halmyros, taking control of the duchy of Athens and …

…Thebes, turning out the Latin lords of Achaia.

The new Aragonese lands, no longer under control of the French, expand into Thessaly and become the duchies of Athens and Neopatria.

The Catalan rule will last without interruption until 1388–1390, when they are defeated by the Navarrese Company under Pedro de San Superano, Juan de Urtubia, and allied with the Florentines under Nerio I Acciaioli of Corinth.

Emperor Andronikos II Palaeilogos recognizes his rebellious grandson as coemperor Andronikos III Palaiologos in 1325, granting him rulership of the provinces of Thrace and Macedonia.

The civil war continues, however, as the younger Andronikos continues to oppose his grandfather, further weakening imperial power against the encircling Ottoman Turks.

Andronikos III finally forces his grandfather to abdicate in 1328, and becomes sole emperor.

The Ottoman Turks, having establishing their Muslim principality in northern Anatolia, continue moving westward, crossing into Thrace in Europe by 1345 at the invitation of self-procaimed emperor John IV Kantakouzenos, who requires their assistance to support his rebellion against the regency for fourteen-year-old Emperor John V Palaiologos.

Orhan now moves against his major Turkmen neighbors to the south.

Taking advantage of internal conflicts, Orhan annexes Karasi in 1345 and gains control of the area between the Gulf of Edremit and Kapidagi (Cyzicus), reaching the Sea of Marmara.

He thus puts himself in a position to end the lucrative monopoly enjoyed by the city of Aydin, that of providing mercenary troops to competing imperial factions in Thrace and at Constantinople.

The expansion also enables the Ottomans to replace Aydin as the principal ally of the emperor John VI Kantakouzenos, from whom Orhan secures the right to ravage Thrace.

The consequent entry of Ottoman troops into Europe gives them a direct opportunity to see the possibilities for conquest offered by imperial Greek decadence.