Orchan was far from obtaining uniform successes against the empire. He was often and bravely opposed by the imperial troops. In 1329, a large army, which had been transported into Thrace in a fleet of seventy ships, was destroyed near Trajanopolis, and most of the Turks were either killed or reduced to slavery. In 1330, a new invasion into Thrace of Turkish cavalry was defeated, and fifteen thousand Turks were slain. Orchan’s attempt in the following year to capture Ismidt failed, and he was obliged to sue for peace. In spite of these disasters, he was always able within a few months to assemble new armies, and to renew the struggle. Already he had succeeded in exacting tribute from nearly the whole of Bithynia. His troops, within two years, invaded Macedonia, Euboea, and Athens, and while Cantacuzenus was with difficulty holding his own against them, another army met Andronicus the Third in Thrace, and took possession of Rodosto--an army, however, which the emperor shortly afterwards destroyed. New recruits were continually making their way across the Dardanelles or the Marmora into Thrace, until, in 1336, the Turkish army in that province met with disaster in an unexpected manner. A band of Tartars from the north made a descent upon them when they heard that they had been successful in a raid upon the Christian population and were carrying off an enormous mass of booty.[86] Three months after the departure of the Tartars a new descent into Thrace was attempted by the Turks. Once again the Greeks were successful, and, in the same year, an army which ravaged the environs of Constantinople was destroyed and the Turkish fleet which brought them captured. [Sidenote: Nicomedia taken (1337).] The efforts of Orchan were more successful in Asia Minor. A division of his army had laid siege again to Ismidt, and the inhabitants, in order to avoid imminent starvation, surrendered. The acquisition, in 1337, of this city, the most important seaport on the Asiatic side of the Marmora, and the head, then as now, of all the roads leading from the capital to every part of Asia Minor, Persia, and Syria, was of the utmost importance.