|Covid-19|Byzantine–Bulgarian War: The Bulgars under Asparukh subjugate the country of current-day Bulgaria, north of the Balkan Mountains. Emperor Constantine IV leads a combined land and sea operation against the invaders and besieges their fortified camp in Dobruja.
Battle of Ongal: The Byzantine army (25,000 men) under Constantine IV is defeated by the Bulgars and their Slavic allies in the Danube Delta. Bulgar cavalry force the Byzantines into a rout, while Constantine (suffering from leg pain) travels to Nesebar to seek treatment.
King Wamba is deposed after an 8-year reign, and forced to retire to a monastery. He is succeeded by Erwig who becomes ruler of the Visigothic Kingdom.
King Perctarit makes his son Cunipert co-ruler of the Lombard Kingdom. He signs a formal peace treaty with Constantine IV.
Pippin of Herstal becomes Mayor of the Palace of Austrasia.
King Cædwalla of Wessex becomes overly ambitious in a power-struggle with his rival, King Centwine, for Wessex overlordship. He is banished into the forests of Chiltern and Andred.
Caliph Muawiyah I, founder of the Umayyad Dynasty, dies.
Yazid Ianatullah, son of Muawiyah I, becomes the sixth caliph (second Umayyad caliph) but Kufans in Mesopotamia rebel and invite Hussein ibn Ali (grandson of Muhammad) to take the throne.
October 10 – Battle of Karbala: Forces under Yazid I kill Hussein ibn Ali, grandson of Muhammad, Prophet of Islam, and his closest supporters. This event leads to the civil war known as the Second Fitna.
In Japan, Princess Uno Sarara is unwell, and Emperor Tenmu begins the erection of the Temple of Yakushi-ji (Nara Prefecture). He makes 100 persons enter religion as priests, wishing her to recover her health.
Hussein ibn Ali is killed at the Battle of Karbala (modern Iraq) by Shimr ibn Dhi 'l-Jawshan, along with most of his family and companions on October 10, 680 AD.
Theodore, archbishop of Canterbury, convenes a synod at Hatfield that clears the English Church from any association with the heresy of Monothelitism.
Wilfrid returns to Northumbria, with papal support, but is imprisoned by King Ecgfrith, and again exiled. He travels to Sussex to evangelise the people.
King Merewalh of Magonsæte founds the monastery of Wenlock Priory (Shropshire). He appoints his daughter Milburga as Benedictine abbess.
Boniface is educated at a Celtic Christian monastery in Exeter, that has been one of many monasteriola built by local landowners and churchmen.
The Book of Durrow is created, probably in Northumbria or on the island of Iona in the Scottish Inner Hebrides (approximate date).
November 12 – The Sixth Ecumenical Council opens in Constantinople, and ends September 16, 681.
Fujiwara no Muchimaro, Japanese politician (d. 737)
Genshō, empress of Japan (d. 748)
Oda of Scotland, Christian saint (approximate date)
Wu Daozi, Chinese painter (d. 760)
January 1 – Javanshir, king of Caucasian Albania (b. 616)
January 30 – Balthild, queen of the Franks
October 9 – Ghislain, Frankish anchorite and saint
Abbas ibn Ali, son of Imam Ali
Ali al-Akbar ibn Husayn, son of Al-Husayn
Ali al-Asghar ibn Husayn, son of Al-Husayn
Habib ibn Madhahir
Husayn ibn Ali, third Shia Imam and grandson of Muhammad (b. 626)
Agatho, pope of the Coptic Orthodox Church
Bhāskara I, Indian mathematician (approximate date)
Cædmon, Northumbrian poet
Ebroin, Mayor of the Palace of Neustria (or 681)
Hilda of Whitby, Northumbrian abbess and saint
Muawiyah I, founder of the Umayyad Caliphate (b. 602)
Umm Salama, wife of Muhammad
Vikramaditya I, king of Chalukya (India)
Wulfoald, Mayor of the Palace of Austrasia
Year 680 (DCLXXX) was a leap year starting on Sunday (link will display the full calendar) of the Julian calendar. The denomination 680 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.