823 CE

Lothair I, eldest son of Emperor Louis I, is crowned co-emperor again by Pope Paschal I at Rome (initiating the papal practice of handing the imperial sword over, as a symbol of temporal power in the Holy Roman Empire). Emperor Michael II defeats the rebel forces under Thomas the Slav in Thrace. He and his supporters are forced to seek refuge in Arkadiopolis (modern Turkey). After five months of blockade, Thomas surrenders and is delivered to Michael, seated on a donkey and bound in chains. He pleads for clemency and prostrates before Michael, but is executed. King Ceolwulf I of Mercia is deposed by Beornwulf, who takes the throne of Mercia. During his rule he rebuilds the Abbey of St. Peter, and presides over two synods at Clofesho.

In the 820s, the 9th century.

Geopolitics & Diplomacy

  • May 30 – Emperor Saga abdicates the throne, after a 10-year reign. He is succeeded by his brother Junna, as the 53rd emperor of Japan.source

Conflict & Security

  • Emperor Michael II defeats the rebel forces under Thomas the Slav in Thrace. He and his supporters are forced to seek refuge in Arkadiopolis (modern Turkey). After five months of blockade, Thomas surrenders and is delivered to Michael, seated on a donkey and bound in chains. He pleads for clemency and prostrates before Michael, but is executed.source

Religion & Belief

  • April 5 – Lothair I, eldest son of Emperor Louis I, is crowned co-emperor again by Pope Paschal I at Rome (initiating the papal practice of handing the imperial sword over, as a symbol of temporal power in the Holy Roman Empire).source
  • King Ceolwulf I of Mercia is deposed by Beornwulf, who takes the throne of Mercia. During his rule he rebuilds the Abbey of St. Peter, and presides over two synods at Clofesho.source

Births

  • June 13 – Charles the Bald, king of the Franks (died 877)source
  • Ermentrude of Orléans, queen of the Franks (died 869)source
  • Pepin II (the Younger), king of Aquitainesource
  • Muhammad I, Muslim emir of Córdoba (died 886)source

Deaths

  • Thomas the Slav, Byzantine general and usurpersource
  • Wulfheard, bishop of Hereford (approximate date)source
  • Ljudevit, duke of the Slavs in Lower Pannoniasource
  • Boniface I, margrave of Tuscanysource
  • Thekla, Byzantine empress (approximate date)source
  • Ceolwulf I, king of Mercia (approximate date)source
  • Adelochus, archbishop of Strasbourg (born 786)source