The central Southern Slav (Serbian) countries—Illyria, Moesia, and Dalmatia—for a long time remained broken up into separate counties. Not before the twelfth century did Rasa become the centre of a Serbian state, founded by Stefan Nemanya (1165), to whom the Serbs owe the famous Nemanya dynasty. After their victory over the Byzantines at Kossovo the Serbs penetrated further and further south towards Macedonia. Under Dušan Silni (1331-1355) Serbian power reached its meridian. He organized the nation into a state and gave the people good laws. In his time Serbia reached from the Save and the Danube to the Gulf of Corinth, and from the Adriatic to Mesta on the frontiers of Thrace and Macedonia. After the battle of Belbushde (1330) even the Bulgars had to acknowledge the supremacy of Serbia. The Serbian Metropolitan of Petcha was made Patriarch, the National Serb Church was founded, and, in the Macedonian town of Skoplye, Dušan Silni proclaimed himself Tsar of the Serbs, Bulgars and Greeks. With an army of 100,000 men he marched on Constantinople in order to establish his throne there, and to be revenged upon the Greeks who had a few years previously called the Ottoman Turks to Europe.[11] But he died on the way,—it is said that he was poisoned by a Greek. Architectural and literary monuments from the age of the Serbian rulers in the thirteenth and fourteenth centuries still clearly show traces of the high degree of culture that had spread from Byzantium, Venice and Florence. But these are merely sparks which the Serbian discriminative genius and natural ability would doubtless have kindled into a bright flame had not the advent of the Turks frustrated the great plans of Dušan Silni. Constantinople would have remained in the hands of a Christian people who love art and progress. No other nation was so well fitted as the Serbs to infuse new life into the culture of the ancients. The presence of this sane and strong young nation would have saved the humanists their flight from Byzantium.