From the fifth century to the advent of the Ottoman Turks in the Balkans in the fourteenth century, invasions from the north and east, especially by the Huns, the Bulgarians, and the Slavs, thinned the indigenous Illyrian population and drove it along the mountainous Adriatic coastal regions. During the crusades in the twelfth and thirteenth centuries, Albania became a thoroughfare for the crusading armies, which used the port of Durres as a bridgehead. By this time the Venetian Republic had obtained commercial privileges in Albanian towns and, after the Fourth Crusade (1204), it received nominal control over Albania and Epirus and took actual possession of Durres and the surrounding areas. In the middle of the thirteenth century Albania fell under the domination of the kings of Naples, and in 1272 armies of Charles I of Anjou crossed the Adriatic and occupied Durres. Thereupon, Charles I issued a decree calling himself Rex Albaniae and creating Regnum Albaniae (the Kingdom of Albania), which lasted for nearly a century. OTTOMAN TURK RULE In the period after the defeat of the Serbs by the Ottoman Turks in 1389 in the battle of Kosovo, most of Albania was divided into a number of principalities under the control of native tribal chieftains, most of whom were subsequently forced into submission by the invading Turks. Some of these chieftains, however, were allowed their independence under Turkish suzerainty. One of the most noted of these was John Kastrioti of Kruje, a region northeast of Tirana, whose four sons were taken hostage by the sultan to be trained in the Ottoman service. The youngest of these, Gjergj, was destined to win fame throughout Europe and to be immortalized as the national hero of his country. Gjergj (b. 1403) soon won the sultan's favor, distinguished himself in the Turkish army, converted to Islam, and was bestowed the title of Skander Bey (Lord Alexander), which, in Albanian, became Skanderbeg or Skenderbey. In 1443 Hungarian King Hunyadi routed at Nish the sultan's armies, in which Skanderbeg held command; Skanderbeg fled to his native land and seized from the Turks his father's fortress at Kruje. His defection and reconversion to Christianity and the creation in 1444 of the League of Albanian Princes, with himself as its head, enraged the Ottomans, who began a series of intense campaigns that lasted until Skanderbeg's natural death in 1468. In his wars against the Turks, Skanderbeg was aided by the kings of Naples and the popes, one of whom, Pope Nicholas V, named him Champion of Christendom. Skanderbeg's death did not end Albania's resistance to the Turks; however, they gradually extended their conquests in Albania and in time defeated both the local chieftains and the Venetians, who controlled some of the coastal towns. The Turkish occupation of the country resulted in a great exodus of Albanians to southern Italy and Sicily, where they preserved their language, customs, and Eastern Orthodox religion.