|Centuries:||6th century – 7th century – 8th century|
|Decades:||620s 630s 640s – 650s – 660s 670s 680s|
|Years:||648 649 650 – 651 – 652 653 654|
|651 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1404|
|Bahá'í calendar||−1193 – −1192|
|English Regnal year||N/A|
|Chinese calendar||庚戌年 (Metal Dog)
3347 or 3287
— to —
辛亥年 (Metal Pig)
3348 or 3288
|- Vikram Samvat||707–708|
|- Shaka Samvat||573–574|
|- Kali Yuga||3752–3753|
|Igbo calendar||−349 – −348|
|Japanese calendar||Hakuchi 2
|Minguo calendar||1261 before ROC
|Thai solar calendar||1194|
|Wikimedia Commons has media related to 651.|
Year 651 (DCLI) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. The denomination 651 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.
- King Clovis II of Neustria and Burgundy marries Balthild, an Anglo-Saxon aristocrat sold into slavery in Gaul. She has been owned by Clovis' mayor of the palace, Erchinoald, who gives her to him to garner royal favour (approximate date).
- King Oswiu of Bernicia declares war on his rival king Oswine of Deira but refuses to engage him in battle, and retreats to Gilling (North Yorkshire). He is betrayed by a friend and murdered by Oswiu's soldiers.
- Œthelwald succeeds his uncle Oswine as king of Deira and allies himself with Oswiu's enemy, king Penda of Mercia. Queen Eanflæd of Bernicia donates the estate of Gilling for the foundation of a monastery.
- King Yazdegerd III of Persia is murdered in a miller's hut near Merv by his followers, ending both Persian resistance to Arab conquest, and the Sassanid Empire.
- The Rashidun army under Abdullah ibn Aamir invade Afghanistan, and capture the main forts in Khorasan (modern Iran). The Muslim Arabs occupy the city of Herat, which surrender peacefully.
- An embassy led by Sa`d ibn Abi Waqqas arrive in the capital Chang'an via an oversea route. They are greeted by emperor Gao Zong who orders the establishment of the first Chinese mosque.
- The Qur'an is compiled by caliph Uthman ibn Affan in its present form. The text become the model from which copies are made and promulgate throughout the urban centers of the Arab world.
- The Hôtel-Dieu de Paris is founded by bishop Landry (Landericus). It becomes the first major hospital in Paris.
- Li Ssu-Hsun, Chinese painter (d. 716)
- August 31 – Aidan, bishop of Lindisfarne
- Braulio, bishop of Zaragoza (b. 590)
- Dayi Daoxin, Chán Buddhist patriarch (b. 580)
- Grasulf II, duke of Friuli (approximate date)
- August 20 – Oswine, king of Deira (England)
- Radoald, duke of Benevento (Italy)
- Yazdegard III, king of the Sassanid Empire