Andronikos III Palaiologos (; 25 March 1297 – 15 June 1341), commonly Latinized as Andronicus III Palaeologus, was the Byzantine emperor from 1328 to 1341. He was the son of Michael IX Palaiologos and Rita of Armenia. He was proclaimed co-emperor in his youth, before 1313, and in April 1321 he rebelled against his grandfather, Andronikos II Palaiologos. He was formally crowned co-emperor in February 1325, before ousting his grandfather outright and becoming sole emperor on 24 May 1328. His reign included the last failed attempts to hold back the Ottoman Turks in Bithynia and the defeat at Rusokastro against the Bulgarians, but also the successful recovery of Chios, Lesbos, Phocaea, Thessaly, and Epirus. His early death left a power vacuum that resulted in the disastrous civil war between his widow, Anna of Savoy, and his closest friend and supporter, John VI Kantakouzenos, leading to the establishment of the Serbian Empire. Life Andronikos was born in Constantinople on 25 March 1297. His father, Michael IX Palaiologos, began reigning in full imperial style as co-emperor circa 1295. In March 1318, Andronikos married Irene of Brunswick, daughter of Henry I, Duke of Brunswick-Grubenhagen. In circa 1321 she gave birth to a son, who died in infancy. In 1320, Andronikos accidentally caused the death of his brother Manuel, after which their father, co-emperor Michael IX Palaiologos, died in his grief. The homicide and the general dissolute behavior of Andronikos III and his coterie, mostly the young scions of the great aristocratic clans of the Empire, resulted in a deep rift in the relations between young Andronikos and his grandfather, still reigning as Emperor Andronikos II Palaiologos. Emperor Andronikos II disowned his grandson Andronikos, who then fled the capital and rallied his supporters in Thrace and began to reign as rival emperor in 1321. Andronikos then waged the intermittent Byzantine civil war of 1321–28 against his reigning grandfather, who granted him to reign as co-emperor Andronikos III. Empress Irene died on 16/17 August 1324 with no surviving child. Theodora Palaiologina, sister of Andronikos III, married the new tsar Michael Shishman of Bulgaria in 1324. Andronikos III, then a widower, married Anna of Savoy in October 1326. In 1327 she gave birth to Maria (renamed Irene) Palaiologina. Andronikos III concluded the Treaty of Chernomen of 1327, an alliance with tsar Michael Shishman of Bulgaria against Stephen Uroš III Dečanski of Serbia. The Byzantine civil war