Byzantium in the Crusading movement

[[File:Miniature of Michael VIII.png|right|thumb|alt=A bearded man wearing a crown and holding a sceptre topped with a cross|Emperor [[Michael VIII Palaiologos]] (from a 14th-century manuscript of the ''Historia'' by [[George Pachymeres]])]]

[[File:Miniature of Michael VIII.png|right|thumb|alt=A bearded man wearing a crown and holding a sceptre topped with a cross|Emperor [[Michael VIII Palaiologos]] (from a 14th-century manuscript of the ''Historia'' by [[George Pachymeres]])]]

Michael{{nbsp}}VIII Palaiologos was crowned emperor on 15{{nbsp}}August 1261. He concluded an agreement with [[William II of Achaea]], captured at Pelagonia, who secured his release by ceding three [[Peloponnese]] fortresses{{refn|group=note|Initially, Michael{{nbsp}}VIII demanded the whole of Achaea; however, William{{nbsp}}II refused, maintaining that he was not entitled to dispose of the principality without the consent of his vassals. He ultimately agreed to cede [[Mistra]] (a fortress he had constructed in 1249), [[Monemvasia]] (the last Byzantine stronghold in the Peloponnese, which he had occupied in 124), and [[Grand Magne]] (a fortress situated at the south-eastern extremity of the peninsula). The agreement was sanctioned at the [[Parliament of Dames]], attended by the wives of the Achaean lords taken captive at Pelagonia.{{sfn|Fine|2009|p=166}}}} to the Byzantines.{{sfn|Lock|2006|p=112}}{{sfn|Treadgold|1997|pp=733, 736-737}} The child emperor John{{nbsp}}IV was deposed and blinded on Michael's orders, prompting Patriarch [[Arsenius of Constantinople]] to excommunicate him.{{sfn|Treadgold|1997|p=737}}

Michael{{nbsp}}VIII Palaiologos was crowned emperor on 15{{nbsp}}August 1261. He made an agreement with [[William II of Achaea]], captured at Pelagonia, who secured his release by ceding three [[Peloponnese]] fortresses{{refn|group=note|Initially, Michael{{nbsp}}VIII demanded the whole of Achaea; however, William{{nbsp}}II refused, maintaining that he was not entitled to dispose of the principality without the consent of his vassals. He ultimately agreed to cede [[Mistra]] (a fortress he had constructed in 1249), [[Monemvasia]] (the last Byzantine stronghold in the Peloponnese, which he had occupied in 124), and [[Grand Magne]] (a fortress situated at the south-eastern extremity of the peninsula). The agreement was sanctioned at the [[Parliament of Dames]], attended by the wives of the Achaean lords taken captive at Pelagonia.{{sfn|Fine|2009|p=166}}}} to the Byzantines.{{sfn|Lock|2006|p=112}}{{sfn|Treadgold|1997|pp=733, 736-737}} The child emperor John{{nbsp}}IV was deposed and blinded on Michael's orders, leading Patriarch [[Arsenius of Constantinople]] to excommunicate him.{{sfn|Treadgold|1997|p=737}}

Following the Greek recovery of Constantinople, [[Pope Urban IV]] proclaimed a crusade against the restored Byzantine Empire, though it gained little support, and French and Spanish clergy refused to fund it.{{sfn|Harris|2022|p=207}} The Pope released William from his oath to Michael to encourage an alliance with Venice and the exiled Latin emperor Baldwin{{nbsp}}II, yet the Byzantines, aided by Genoa, seized Aegean islands and captured the three fortresses. The prolonged conflict depleted the treasury, leading Michael to seek reconciliation with Venice in 1265.{{sfn|Treadgold|1997|pp=737-739}}

Following the Greek recovery of Constantinople, [[Pope Urban IV]] proclaimed a crusade against the restored Byzantine Empire, though it won little support, and French and Spanish clergy refused to fund it.{{sfn|Harris|2022|p=207}} To promote an alliance with Venice and the exiled Latin emperor Baldwin{{nbsp}}II, the Pope released William from his oath to Michael. Yet the Byzantines, aided by Genoa, seized Aegean islands and the three fortresses. The conflict drained the treasury, prompting Michael to seek reconciliation with Venice in 1265.{{sfn|Treadgold|1997|pp=737-739}} Meanwhile, the [[Mamluk Sultanate|Mamluks]] supplanted the Ayyubids as the dominant Muslim power in the Middle East and [[Siege of Antioch (1268)|took Antioch]] in 1268. Michael pursued what Harris calls "versatile diplomacy", concluding treaties with rival powers.{{refn|group=note|Michael's agreement with the Mamluk sultan [[Baybars]] confirmed his right to appoint the Orthodox patriarch of Jerusalem, and secured the supply of Cuman troops to the Mamluks. He also allied with Mongol rulers, marrying his daughters to [[Abaqa Khan|Abaqa]] of the [[Ilkhanate]], and his [[Nogai Khan|Nogai]] from the [[Golden Horde]].{{sfn|Harris|2022|pp=208-209}}{{sfn|Laiou|2017|p=805}}}}{{sfn|Harris|2022|pp=208-211}}{{sfn|Laiou|2017|p=805}}

Meanwhile, the [[Mamluk Sultanate|Mamluks]] supplanted the Ayyubids as the dominant Muslim power in the Middle East. Sultan [[Baybars]] captured Crusader castles and [[Siege of Antioch (1268)|took Antioch]] in 1268. Michael pursued what Harris terms "versatile diplomacy", concluding treaties with rival powers. His agreement with Baybars confirmed his right to appoint the Orthodox patriarch of Jerusalem, and secured the supply of Cuman troops to the Mamluks. He also allied with Mongol rulers, marrying his daughters to [[Abaqa Khan|Abaqa]] of the [[Ilkhanate]] and [[Nogai Khan|Nogai]] from the [[Golden Horde]].{{sfn|Harris|2022|pp=208-211}}{{sfn|Laiou|2017|p=805}}

====Charles of Anjou and the church union====

====Charles of Anjou and the church union====