920

Gold solidus of Romanos I with his eldest son, Christopher Lekapenos (right).

Events

December 17 – Romanos I has himself crowned co-emperor of the Byzantine Empire. He shares the throne with the 15-year-old Constantine VII (his son-in-law), and constructs an alternative palace at Constantinople with an adjoining monastery near the Great Palace. Though Constantine retains his formal position as first on the protocol list, Romanos becomes sole ruler.<ref>Timothy Reuter (1999). The New Cambridge Medieval History: Volume III, p. 563. Template:ISBN.</ref>

The nobles of Lotharingia under Gilbert, duke of Lorraine, revolt against King Charles III ("the Simple"). They recognize King Henry I ("the Fowler") as their sovereign. Charles invades Lotharingia as far as Pfeddersheim (near Worms), but retreats when he learns that Henry is mobilizing an army to attack the West Frankish Kingdom.<ref>Timothy Reuter (1999). The New Cambridge Medieval History: Volume III, p. 314. Template:ISBN.</ref>
Henry I conquers Utrecht (modern-day Netherlands), which has been in possession of the Vikings for 70 years. Balderic, bishop of Utrecht, moves his seat back from Deventer to Utrecht (approximate date).

High-Reeve Ealdred I, ruler of the former kingdom of Bernicia (Northumbria), and his brother Uhtred, submit to the overlordship of King Edward the Elder (approximate date).
The Welsh ruler Hywel Dda ("the Good") merges Dyfed and Seisyllwg, establishing a new kingdom known as Deheubarth.

July 26 — At the Battle of Valdejunquera, the Muslim forces of the Emir Abd-ar-Rahman III of Córdoba, defeat the Christian armies of King Ordoño II of León and King Sancho I of Pamplona. The decisive battle at the Val de Junquera takes place following the Emir's pre-emptive strike and his invasion of the upper Douro valley and the capture of Osma. The Arab army proceeds on to the upper Ebro, restoring and replenishing Umayyad garrisons in the region.<ref>Timothy Reuter (1999). The New Cambridge Medieval History: Volume III, p. 675. Template:ISBN.</ref>

Emperor Taizu of the Khitan Empire orders the adoption of a written script by the Khitan, resulting in the creation of Khitan "Large Script."

Muslim chroniclers in Baghdad record an unusually cold summer.<ref>Domínguez-Castro, Fernando; Vaquero, José Manuel; Marín, Manuela; Gallego, María Cruz; García-Herrera, Ricardo. "How useful could Arabic documentary sources be for reconstructing past climate?" Weather 67(3): 76-82 Template:Doi March 2012.</ref>