Alexios Palaiologos ( despot ) Alexios Palaiologos ( died 1203 ) was a Byzantine nobleman , son - in - law of Emperor Alexios III Angelos ( r . 1195 – 1203 ) and his heir apparent from 1199 to his death . Throughout this time , he was actively involved in the suppression of several revolts and riots against the emperor . Through his daughter , he became one of the progenitors of the imperial line of the Palaiologos dynasty . Biography . Alexios ' s origins are obscure . His family was wealthy and mostly known as civil and military officials under the Komnenian emperors . Alexios ' s father was probably the " sebastos " and " megas hetaireiarches " George Palaiologos , the son or grandson of Alexios I Komnenos ' s staunchest supporter George Palaiologos . Through his grandmother , Alexios shared in the blood of the Komnenian house . In circa 1198 , Alexios was chosen by Emperor Alexios III , who was without male offspring , to wed his eldest daughter , Irene . She was a widow of Andronikos Kontostephanos , and Alexios Palaiologos was forced to divorce his own beautiful first wife ( whose name is unknown ) to marry her . The wedding took place in spring 1199 and was accompanied by lavish celebrations . Alexios thus became the imperial heir apparent , and was elevated to the rank of despot . At the same time , the emperor ' s second daughter Anna , also a widow , was wed to Theodore Laskaris , the future founder of the Empire of Nicaea . Shortly afterwards , both imperial sons - in - law were sent alongside general Manuel Kamytzes against the rebel Ivanko in Thrace . During this campaign , in the siege of Kritzimos , Alexios ' s father George was killed . The campaign failed when the Byzantine force was trapped in an ambush and Kamytzes was captured . This success emboldened Ivanko , who now claimed the imperial title . In spring 1200 , Alexios III pretended to be willing to begin negotiations , and sent Alexios Palaiologos to meet the rebel . Alexios gave solemn promises of safety , but when Ivanko appeared in the imperial camp , he was arrested and executed . In February of the same year , Alexios had been called upon to help with the riots that broke out in Constantinople in protest against the embezzlement of charitable donations by the prison warden John Lagos . A large mob had taken control of the capital ' s prisons and opened them , and battled the guards of the emperor , who was away at Chrysopolis . Alexios Palaiologos led troops into the city and suppressed the revolt after inflicting heavy casualties on the populace . In July 1201 , Alexios was instrumental in the suppression of the attempted coup by John Komnenos the Fat . After the rebels had seized control of most of the Great Palace , Alexios was sent by the emperor with troops and boats from the Blachernae to the eastern shore of the city . There they met up with the Great Palace ' s guard , and cleared the palace and the Hippodrome of the supporters of the usurper , who was caught and beheaded . In February 1201 or 1202 , Alexios was injured when the imperial tent collapsed during an earthquake , but in the same summer he led the campaign that subdued the rebellion of governor John Spyridonakes in eastern Macedonia , forcing the latter to flee to Bulgaria . Alexios died at a relatively early age in 1203 , of natural causes according to Theodore Skoutariotes . His death occurred before the deposition and flight of Alexios III in the face of the siege of Constantinople by the Fourth Crusade . Family . Aside from his father George , Alexios had an unnamed aunt , who married John Bryennios , and an uncle , the " sebastos " Constantine . The name of his mother is not known , nor does it appear that he had siblings . From his marriage with Irene Angelina , he had one daughter , Theodora , who married the " megas domestikos " Andronikos Palaiologos , the son of the " megas doux " Alexios Palaiologos ( from a different branch of the Palaiologos line ) and of Irene Komnene . They had numerous children the most prominent of whom was Michael VIII Palaiologos , who became emperor of Nicaea in 1259 and restored the Byzantine Empire in 1261 .