Factless: Not only Serbia but Hungary, Poland, Austria, Venice, Constantinople and the Pope all fought the Turks. See The Catholic Encyclopedia:1913]:
Googlebooks.google.com/books?id=kO078Q2kb9wC...]
“Since 1389 when Servia was conquered by the Osmanli power at the battle of Kosova (also called Amselfeld, “Field of the Blackbirds”), the Turks had slowly but steadily advanced against Hungary. ... To safeguard the Hungarian frontier, Sigismund obtained from Stephen Lazarevics, ruler of Servia... in 1426, the Servian fortresses on the border of the two countries, but he was not able to hold them against the Turks.... Hunyady fought successfully against the Turks. ... Constantinople was taken by the Turks (1453), who now turned all their strength against Hungary. Hunyady won, indeed, the brilliant victory over them at Belgrad (1456) ...
Quick question, who fought more against the Turks, Servs or Albanians? Google Stephen Lazarevic