|Centuries:||6th century – 7th century – 8th century|
|Decades:||620s 630s 640s – 650s – 660s 670s 680s|
|Years:||654 655 656 – 657 – 658 659 660|
|657 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1410|
|Bahá'í calendar||−1187 – −1186|
|English Regnal year||N/A|
|Chinese calendar||丙辰年 (Fire Dragon)
3353 or 3293
— to —
丁巳年 (Fire Snake)
3354 or 3294
|- Vikram Samvat||713–714|
|- Shaka Samvat||579–580|
|- Kali Yuga||3758–3759|
|Igbo calendar||−343 – −342|
|Minguo calendar||1255 before ROC
|Thai solar calendar||1200|
|Wikimedia Commons has media related to 657.|
Year 657 (DCLVII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. The denomination 657 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.
- Grimoald the Elder, mayor of the palace of Austrasia, is deposed by Clovis II, king of Neustria. He captures his son Childebert the Adopted executing them both.
- Clovis II dies and is succeeded by his eldest son Chlothar III, age 5, who becomes king of Neustria and Burgundy under the regency of his mother Balthild.
- Battle of Siffin: Muslim forces under Ali ibn Abi-Taleb fight an inconclusive battle against Muawiyah, on the banks of the Euphrates, near Ar-Raqqah (Syria).
- Tang campaigns against the Western Turks: Emperor Gao Zong dispatches a military campaign led by Su Dingfang. He annexes the Western Turkic Khaganate.
- Gao Zong commissions the pharmacology publication of an official materia medica documenting the use of 833 different substances for medicinal purposes.
- June 1 – Pope Eugene I dies at Rome after a reign of nearly 2½ years. He is succeeded by Vitalian as the 76th pope.
- Hilda, Anglo-Saxon abbess, founds a monastery at Streaneshalch on the Yorkshire coast at Whitby (England).
- Childebert the Adopted, king (usurper) of Austrasia
- Clovis II, king of Neustria and Burgundy (or 658)
- Grimoald the Elder, Mayor of the Palace (b. 616)
- November 12 – Livinus, Irish apostle
- June 1 – Pope Eugene I
- Talorgan I, king of the Picts