644

By place

Byzantine Empire

• Valentinus, Byzantine general, attempts to usurp the throne of his son-in-law Constans II. He appears at the gates of Constantinople with a contingent of Byzantine troops, and demands to be crowned emperor. His claim is rejected, and Valentinus is lynched by the populace.

  Britain

• Oswine, son of the late king Osric of Deira, manages, despite armed objections from King Oswiu of Bernicia, to establish himself as king of Deira. His succession, probably the choice of the people of Deira, splits the Kingdom of Northumbria.

  Arabian Empire

• October 31 - Piruz Nahavandi commits suicide.
• November 3 - Caliph Umar, age 65, dies of wounds inflicted on October 31 by the Persian slave Piruz Nahavandi at Medina, after a 10-year reign. On his death bed he appoints a committee to determine his successor. They select Uthman ibn Affan, who becomes caliph of the Rashidun Caliphate.

  Asia

• Emperor Taizong of the Tang Dynasty sends a Chinese expeditionary force, to invade and annex the Tarim Basin kingdom of Karasahr in Xinjiang, a vassal of the Western Turkic Khaganate. The oasis state is conquered, and Western Turks sent to assist Karasahr are defeated by the Tang forces.