Owing to the adroit leadership of their chief, Halil, and to the impotence of Michael, whose Slavic mercenaries had deserted him and withdrawn into Bulgaria, these Turks were soon able to throw Macedonia and Thrace into so great anarchy that communication by land between Salonika and the capital was no longer safe.[59] And yet Halil had only eighteen hundred men under his command! In 1311, shortly after the Catalans had left, Halil concluded with Andronicus and Michael an agreement by which he and his companions in arms were to have a safe-conduct and free passage across the Hellespont. But the Greeks, in violation of one of the most important points of this arrangement, attempted to take from the Turks their booty. Halil, instead of quitting European soil, sent for reinforcements. The imperial army suffered a decisive defeat, and Michael fled, having abandoned his personal baggage. In insolent triumph, Halil adorned himself with the imperial insignia.[60] All the region around the Hellespont and the Gulf of Saros remained for three years without cultivation. So desperate did the situation become that Michael was compelled to seek aid of the Genoese and the Serbians. In 1314 the Turks of Halil were entrapped near Gallipoli and massacred. But at what a price! The Serbians, whose co-operation had won the day for the Greeks, saw eastern Macedonia and the open sea. They liked it. New troubles began to brew for the Byzantines. There were other long-standing troubles threatening from abroad. In the East, the Mongols had overrun southern Russia, and were as great a nightmare to Andronicus as the Goths had formerly been to Valens. The rulers of Constantinople did not hesitate to purchase security on the Black Sea by truces, which were sealed with the sacrifice of purple-born princesses to pagan harems, and by humble protestations of friendship to khans who treated the imperial ambassadors as the envoys of a vassal.[61]