Year 681 (DCLXXXI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. The denomination 681 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.
|Ab urbe condita||1434|
|Balinese saka calendar||602–603|
|Chinese calendar||庚辰年 (Metal Dragon)|
3377 or 3317
— to —
辛巳年 (Metal Snake)
3378 or 3318
|- Vikram Samvat||737–738|
|- Shaka Samvat||602–603|
|- Kali Yuga||3781–3782|
|Minguo calendar||1231 before ROC|
|Seleucid era||992/993 AG|
|Thai solar calendar||1223–1224|
807 or 426 or −346
— to —
808 or 427 or −345
- Byzantine–Bulgarian War: Emperor Constantine IV is forced to acknowledge the Bulgar state in Moesia, and to pay protection money to avoid further inroads into Byzantine Thrace. Consequently, Constantine creates the Theme of Thrace of the Byzantine Empire (located in the south-eastern Balkans).
- Constantine IV has his brothers Heraclius and Tiberius mutilated, so they will be unable to rule. He orders that their images no longer appear on any coinage, and that their names be removed from official documentation. Constantine raises his son Justinian II to the throne as joint emperor (Augustus).
- Autumn – A military revolt breaks out in the Anatolic Theme (modern Turkey). The Byzantine army marches to Chrysopolis, and sends a delegation across the straits of the Hellespont to Constantinople, demanding that the two brothers should remain co-emperors alongside Constantine IV.
- Constantine IV agrees to a compromise, and persuades the army to return to their barracks in Anatolia. He invites the leaders of the rebellion to come to Constantinople and consult the Senate as to how to implement the terms. On their arrival, he arrests the leaders and has them hung at Sycae.
- January 9 – Twelfth Council of Toledo: King Erwig of the Visigoths initiates a council, in which he implements diverse measures against the Jews. Laws against violence to slaves are suppressed.
- King Æthelwalh of Sussex gives Wilfrid, exiled bishop of York, lands in Selsey to found a cathedral, named Selsey Abbey.
- King Ecgfrith of Northumbria requests that the monks of Monkwearmouth found a new monastery at Jarrow (or 682).
- A Muslim Arab army led by Uqba ibn Nafi reaches Morocco, before being forced back into Cyrene by the Berbers.
- Armenians, Albanians, and Iberians rise in rebellion against the Umayyad Caliphate (approximate date).
- In Japan the Asuka Kiyomihara Code is commenced under Emperor Tenmu.
- Kutluk Khan revolts and establishes the Second Turkic Khaganate.
- Kusakabe, second son of Tenmu, is made crown prince.
- Sinmun becomes king of the Korean kingdom of Silla.
- January 10 – Pope Agatho dies at Rome of plague after a 2½-year reign, in which he has persuaded Constantine IV to abolish the tax heretofore levied at the consecration of a newly elected pope.
- September 16 – The Sixth Ecumenical Council (see 680) ends at Constantinople. The council reaffirms the Orthodox doctrines of the Council of Chalcedon in 451, and condemns monothelitism.
- Bellinger, Alfred Raymond; Grierson, Philip (1968). Catalogue of the Byzantine coins in the Dumbarton Oaks Collection and in the Whittemore Collection. Dumbarton Oaks. OCLC 847177622.
- Bury, John Bagnall (1889). A History of the Later Roman Empire from Arcadius to Irene. II. London: Macmillan.
- Kazhdan, Alexander Petrovich, ed. (1991). The Oxford Dictionary of Byzantium. New York and Oxford: Oxford University Press. ISBN 978-0-19-504652-6.
- Norwich, John Julius (1990). Byzantium: The Early Centuries. Penguin. ISBN 0-14-011447-5.
- Tucker, Spencer C., ed. (2010). A Global Chronology of Conflict. I: Ca. 3000 BCE–1499 CE. ISBN 978-1-85109-672-5.