During the fourteenth century the Latins' hold on those fragments of the great empire of Romania which they had acquired after the overthrow of the Byzantine emperor in 1204 became increasingly precarious. In the Morea, as the Peloponnese was then known, the foremost Frankish houses, the Villehardouin, the Courtenay, the de la Roche and others, were extinguished. The French magnates faced hostility not only from the Greeks and Turks, but also from the Catalans and the Italianate elements to whom their lands passed through conquest, marriage or princely favour. A turning point in this process was the slaughter of many male members of the old Frankish aristocracy by the Catalan companies and their Turkish allies in a great battle near Thebes in 1311, at which Gautier de Brienne, who had succeeded his kinsman Guy de la Roche as Duke of Athens and Neopatras in 1309, was killed. Gautier's duchies were occupied by the Catalans, who were acting independently of the Aragonese King of Sicily, though they subsequently rendered a vague formal allegiance to a line of Siculo-Aragonese dukes. The Catalans did not take Corinth, which lay on the isthmus separating the Duchy of Athens from the Morea, and the Brienne family retained effective possession of its lands beyond Corinth, around Argos and Nauplia, which continued to form part of the Principality of Achaea.