678

678 in various calendars
Gregorian calendar	678; DCLXXVIII
Ab urbe condita	1431
Armenian calendar	127; ԹՎ ՃԻԷ
Assyrian calendar	5428
Balinese saka calendar	599–600
Bengali calendar	85
Berber calendar	1628
Buddhist calendar	1222
Burmese calendar	40
Byzantine calendar	6186–6187
Chinese calendar	丁丑年 (Fire Ox); 3375 or 3168; — to —; 戊寅年 (Earth Tiger); 3376 or 3169
Coptic calendar	394–395
Discordian calendar	1844
Ethiopian calendar	670–671
Hebrew calendar	4438–4439
Hindu calendars
- Vikram Samvat	734–735
- Shaka Samvat	599–600
- Kali Yuga	3778–3779
Holocene calendar	10678
Iranian calendar	56–57
Islamic calendar	58–59
Japanese calendar	Hakuchi 29; (白雉２９年)
Javanese calendar	570–571
Julian calendar	678; DCLXXVIII
Korean calendar	3011
Minguo calendar	1234 before ROC; 民前1234年
Nanakshahi calendar	−790
Seleucid era	989/990 AG
Thai solar calendar	1220–1221
Tibetan calendar	阴火牛年; (female Fire-Ox); 804 or 423 or −349; — to —; 阳土虎年; (male Earth-Tiger); 805 or 424 or −348

Millennium:	1st millennium
Centuries:	6th century; 7th century ; 8th century;
Decades:	650s; 660s; 670s ; 680s; 690s;
Years:	675; 676; 677; 678 ; 679; 680; 681;

Year 678 (DCLXXVIII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 678 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.

Events

July 27 – The Siege of Thessalonica (676–678) ends, when the Sclaveni withdraw.
Autumn – Siege of Constantinople: Emperor Constantine IV confronts the Arab besiegers in a head-on engagement. The Byzantine fleet, equipped with Greek fire, destroys the Muslim fleet at Sillyon,^[1]^[2]^[3]^[4] ending the Arab threat to Europe, and forcing Yazid (a son of caliph Muawiyah I) to lift the siege on land and sea. The victory also frees up forces that are sent to raise the two-year siege of Thessalonica by the local Slavic tribes.

King Æthelred of Mercia defeats the Northumbrian forces under King Ecgfrith, in a battle near the River Trent. Archbishop Theodore helps to resolve differences between the two, Æthelred agreeing to pay a weregild to avoid any resumption of hostilities (approximate date).

April 27 – Emperor Tenmu holds divination for the purpose of proceeding to the Abstinence Palace.
May 3 – Princess Tōchi suddenly takes ill and dies within the palace. Tenmu, her father, is unable to sacrifice to the Gods of Heaven and Earth.
May 10 – Tōchi is buried at a place which could be Akō (Hyōgo Prefecture). Tenmu is graciously pleased to raise lament for her.

Wilfrid, bishop of York, is at the height of his power and owns vast estates throughout Northumbria. After his refusal to agree to a division of his see, Ecgfrith and Theodore, archbishop of Canterbury, have him banished from Northumbria.
April 11 – Pope Donus dies at Rome, after a reign of 1 year and 160 days. He is succeeded by Agatho I, who becomes the 79th pope. He is the first pope to stop paying tribute to Emperor Constantine IV upon election.
In Japan, the national worshiping to the Gods of Heaven and Earth is planned. Tenmu tries to select his daughter Tōchi as a Saiō to make her serve the Gods. However, Tōchi suddenly takes ill and dies.
The Beomeosa temple complex in Geumjeong-gu (modern South Korea) is constructed, during the reign of King Munmu of Silla.

Haldon, John F. (1990). Byzantium in the Seventh Century: The Transformation of a Culture (revised ed.). Cambridge University Press. ISBN 978-0-521-31917-1.
Lilie, Ralph-Johannes (1976). Die byzantinische Reaktion auf die Ausbreitung der Araber. Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jhd [Byzantine Reaction to the Expansion of the Arabs. Studies on the Structural Change of the Byzantine State in the 7th and 8th Cent.] (in German). Munich: Institut für Byzantinistik und Neugriechische Philologie der Universität München. OCLC 797598069.
Mango, Cyril; Scott, Roger (1997). The Chronicle of Theophanes Confessor. Byzantine and Near Eastern History, AD 284–813. Oxford University Press. ISBN 0-19-822568-7.
Treadgold, Warren (1997). A History of the Byzantine State and Society. Stanford, California: Stanford University Press. ISBN 0-8047-2630-2.