On This Day: December 11th

The Root and Branch petition, signed by 15,000 Londoners calling for the abolition of the episcopacy, is presented to the Long Parliament.

A surprise attack by forces under the command of Charles Emmanuel I, Duke of Savoy, and his brother-in-law, Philip III of Spain, is repelled by the citizens of Geneva. (Commemorated annually by the Fête de l'Escalade.)

The Nyköping Banquet (Swedish: Nyköpings gästabud) takes place as King Birger of Sweden celebrates Christmas at Nyköping Castle. Among the guests are his two brothers Duke Valdemar and Duke Eric, who later that night are imprisoned and eventually starved to death in the castle dungeon.

Battle of Orewin Bridge: Llywelyn ap Gruffudd, the last native Prince of Wales, is killed at Cilmeri near Builth Wells in mid-Wales.

Treaty of Benavente: the heiresses of the Kingdom of León renounce their throne to King Ferdinand III of Castile

Michael V, adoptive son of Empress Zoë of Byzantium, is proclaimed emperor of the Eastern Roman Empire.

Byzantine Emperor Nikephoros II Phokas is assassinated by his wife Theophano and her lover, the later Emperor John I Tzimiskes.

Assassination of the Abbasid caliph al-Mutawakkil by the Turkish guard, who raise al-Muntasir to the throne, start of the "Anarchy at Samarra".

Julian enters Constantinople as sole Roman Emperor.

Emperor Xian of Han is forced to abdicate the throne by Cao Cao's son Cao Pi, ending the Han dynasty.