Stefan Uroš IV Dušan (Serbian Cyrillic: Стефан Урош IV Душан, pronounced [stêfaːn ûroʃ tʃětʋr̩ːtiː dǔʃan] (listen)), known as Dušan the Mighty (Serbian: Душан Силни / Dušan Silni; circa 1308 – 20 December 1355), was the King of Serbia from 8 September 1331 and Tsar (or Emperor) and autocrat of the Serbs and Greeks (or Romans) from 16 April 1346 until his death in 1355.

Dušan conquered a large part of southeast Europe, becoming one of the most powerful monarchs of the era. Under Dušan's rule, Serbia was the major power in the Balkans, and an Eastern Orthodox multi-ethnic and multi-lingual empire that stretched from the Danube in the north to the Gulf of Corinth in the south, with its capital in Skopje. He enacted the constitution of the Serbian Empire, known as Dušan's Code, perhaps the most important literary work of medieval Serbia. Dušan promoted the Serbian Church from an archbishopric to a patriarchate, finished the construction of the Visoki Dečani monastery (now a UNESCO site), and founded the Monastery of the Holy Archangels, among others. Under his rule, Serbia reached its territorial, political, economic, and cultural peak.Dušan died in 1355, seen as the end of resistance against the advancing Ottoman Empire and the subsequent fall of the Eastern Orthodox Church in the region.