As a military power the revived Greek Empire was pathetically feeble. Its last great leader in war was Michael VIII, who had retaken Constantinople from the Latins, a conquest on a slight scale, since the Latins were even weaker than their opponents. The measure of Greek offensive is attested by the inability of any Greek Emperor to retake the Asiatic provinces from the Turk, to annex the Empire of Trebizond, to resist the Slavs in the Balkans, or to reoccupy the islands of the Ægean and drive the Franks from Greece. Even in the interior there was no effective administration. In every Greek city there were colonies of Italian merchants, either Genoese or Venetian, who formed independent communities under their own podestà. The army was filled with foreign contingents, who were not even mercenary troops, because the Empire could not afford to hire soldiers. They were auxiliary forces, organized as complete military units under their own natural chief, and were a constant menace. When they saw fit, they pillaged the country and sometimes fought among themselves. They were under no kind of control from the central or local authorities; within their own camps on the frontiers, in the provinces, even under the walls of the capital itself, they obeyed their own commanders and not the Emperor. One of the most radical changes for the worse in the revived Greek Empire, a change that marked the contrast with the heroic period of Byzantine military enterprise, was the lack of a fleet. For his naval operations the Emperor depended on the Venetians or Genoese, a most unsatisfactory arrangement, for, owing to the jealousy of these two commercial states, if one were the ally of Constantinople, the other was certain to be on the opposite side. In 1296 the Venetians, after defeating their rivals at sea, laid siege to the Pera and Galata sections of Constantinople, the seat of the Genoese colony, and in setting fire to the quarter destroyed many Greek houses. Later on, the Genoese revenged themselves by massacring the Venetian residents of Constantinople. The anarchy was increased when, owing to rival claimants to the throne, open civil war broke out, as it did frequently in the course of the fourteenth century. Cantacuzene, an official in the imperial palace, who became rival Emperor, while Anna of Saxony was regent during the minority of her son, John V, after the death of his father, Andronicus III, allied himself with the Servians and with the Seldjouk emir of Konia. Anna tried to strengthen her side by calling upon Ourkhan, the Osmanli Sultan. In the war that followed the Turks were authorized to seize the citizens of the empire, and the rival governments placed at the disposition of their Mohammedan allies seaports and vessels. The captives taken were sent to Asia and sold as slaves in the Turkish emirates.