In 1499 the city was again in danger of a Turkish attack, and envoys were sent to Hungary to raise a force of mercenaries. The reasons for this hostility, besides the usual desire on the part of the Turks to occupy so excellent a port, were due to the fact that many of the Bosnian and Herzegovinian nobles who had taken refuge at Ragusa frequently made raids into the conquered territory, doing much damage to its new occupants. The Turks also believed that the Ragusans sometimes helped even the Venetians. In fact, the reports of the Ragusan “exploratores” (spies) and traders in all parts of the Ottoman dominions were often transmitted to other Christian potentates besides the King of Hungary. On this occasion the Venetians were informed that the Turkish fleet was to be ready in May, and that bridges were being built across all the rivers in Albania.[427] But apparently the Sultan put off his expedition, and decided to send only four ships to Apulia to fetch the body of Djem.[428] He altered his plans again in June, got ready a large fleet, and concentrated the army at Üsküb. In July the land force had advanced northward to Pirot; by August it had crossed into Albania, and was encamped on the coast opposite Corfu. The fleet left Gallipoli, and artillery was sent to Albania and the Morea.[429] The last years of the fifteenth century and the first of the sixteenth were marked by plagues and earthquakes at Ragusa. Razzi mentions epidemics of various kinds in 1500, 1503, and 1505, when 1600 persons died; and earthquakes in 1496 and 1504. The Republic’s trade was also harried by the numerous corsairs which infested the Adriatic and the Mediterranean. In 1510 seven Candiot pirate barques captured two Ragusan galleys laden with Ragusan goods worth 30,000 ducats, as well as valuable property belonging to some Florentines; but the stolen goods were recovered through the action of the Venetian Senate. The Sultan of Egypt, who, like other Muhamedan potentates, did not always distinguish between one Christian race and another, detained five Ragusan vessels at Alexandria as a reprisal for the capture of some Moorish ships by the Knights of Rhodes. But the Sultan was pacified, and he returned the ships and granted the Ragusans permission to trade with the East Indies through Egypt and Syria. In 1509 the Republic had availed itself of Venice’s difficulties consequent on the League of Cambrai to obtain the removal of trade restrictions, and it provided Venice with grain and war stores in return.[430] The following year it informed the Venetian Government that the Sultan had made a truce with Hungary in order to wrest Dalmatia from them. In 1512 the Sultan once more raised the tribute from 3000 to 5000 ducats, and threatened the city with an expedition of 500 sail, probably in consequence of the assistance given to Venice; but again the danger passed off.