821

821 (DCCCXXI) was a common year beginning on a Tuesday of the Julian calendar, effective on that date.

Events

• Tang Mu Zong accedes to the imperial throne of China.
• Thomas the Slave asedia Constantinople.

Deaths

• Theodulph of Orleans, holy Spanish.
• Benito de Aniane, Benedictine monk.
• Varaz Terdat II dies.