Under Dushan Serbia had very nearly reached her highest ambition--complete dominion over the Balkan Peninsula. Dushan ruled also a large part of the former Byzantine lands in Europe.
Of farther-reaching good for Serbia than his territorial conquests was the Zakonik or Code of Laws, completed in 1354 under Dushan's direction. It contained not only the best of the old, but many new, laws resulting from Dushan's knowledge of his country's needs. It ranks high among medieval codes of law. After his death, his empire separated itself into its elements--a number of small states whose rulers were fighting one another while the Turks were subduing Thrace.
With the death of Dushan in 1355 the greatness of Serbia also passed away. His son, Urosh, could not hold what his father had gained, and little by little parts of his Empire fell off from the center, until but a small fragment remained. Yet there were still many stout-hearted Serbs--many who wished to do their utmost to throw off the Turks now pressing upon them. When Urosh died childless, the direct Nemanya dynasty came to an end, but in 1371 Lazar Grebelyanovitch of the Nemanya family was elected ruler of the Serbs. Though called Tsar, he would not formally take the title. Devoted to his country, he threw all his energy into forming a Christian League against the Turks.
But the wily Oriental circumvented him by attacking the members of the League one by one. For nearly twenty years after that there were many encounters between Turks and Serbians. At the first attack on Nish, Serbia so humbled herself as to agree to pay tribute in gold and in soldiers for the Sultan's armies on condition the Turks would leave her alone.
Later Lazar did his utmost to save poor Serbia from further disgrace. He united with the Ban of Bosnia, also a descendant of Stephen Nemanya, and together they gained many small victories. After once defeating the invading Turks under Murat I the Serbs had to stand a second time opposed to Murat and a well-trained force of Turkish soldiers. Against the Turks were drawn up the full strength of Serbia, Albania, and Bosnia.
There on the field of Kossovo, the "field of blackbirds," June 15, 1389, was fought one of the decisive battles of history. It was a bitter defeat for Serbia, though as many Turks as Serbs perished on the field. On the eve of the battle Murat I had been assassinated. The brave Lazar with the flower of the Serb nation lay dead--Lazar first made prisoner, then beheaded. Of all Serbian rulers, the memory of Lazar was held the dearest. "A pious and generous prince, a brave but unsuccessful general."