Simeon Uroš
Simeon Uroš Nemanjić, nicknamed Siniša (Serbian Cyrillic: Симеон Урош Синиша Немањић), also known in Greek as Symeōn Ouresēs Palaiologos (Συμεών Ούρεσης Παλαιολόγος), was the Tsar of Epirus from 1359 to 1366, and of Thessaly from 1359 until his death in 1370. He governed Epirus and Acarnania under his half-brother Emperor Stephen Uroš IV Dušan of Serbia (r. 1331-1355) from 1348. After Stephen's death in 1355, Simeon ruled these regions as self-proclaimed Emperor of the Serbs and Greeks in rivalry with his nephew Stephen Uroš V of Serbia.
Life
Simeon Uroš, nicknamed Siniša, was the son of King Stephen Uroš III Dečanski of Serbia by his second wife, Maria Palaiologina, the daughter of the John Palaiologos, a grandson of Emperor Michael VIII Palaiologos.
His half-brother Stephen Dušan proclaimed himself Emperor in 1346, and conquered Epirus and Acarnania in 1348. He appointed Simeon as governor of these regions, and granted him the title of despotes, traditionally reserved for the brothers and younger sons of Byzantine Emperors. Simeon Uroš consolidated his position with the local aristocracy by marrying Thomais Orsini, the daughter of the former ruler of Epirus, John II Orsini.