Stephen Dušan (Serbian: Stefan Dušan/Стефан Душан, pronounced [stêfaːn ûroʃ tʃětʋr̩ːtiː dǔʃan]), commonly known as Stephen Dušan and Dušan the Mighty (Dušan Silni/Душан Силни; c. 1308 – 20 December 1355), was the King of Serbia (from 8 September 1331) and Emperor of the Serbs and Greeks (from 16 April 1346) until his death on 20 December 1355. Dušan managed to conquer a large part of Southeast Europe, becoming one of the most powerful monarchs in his time. He enacted the constitution of the Serbian Empire in Dušan's Code, one of, if not the most important work of medieval Serbia. Dušan promoted the Serbian Church from an Archbishopric to a Patriarchate, finished the construction of the Visoki Dečani-monastery (UNESCO site), and founded the Saint Archangels Monastery, among others. Under his rule Serbia reached its territorial, economical, political and cultural peak.