|Ab urbe condita||1424|
|Balinese saka calendar||592–593|
|Chinese calendar||庚午年 (Metal Horse)|
3367 or 3307
— to —
辛未年 (Metal Goat)
3368 or 3308
|- Vikram Samvat||727–728|
|- Shaka Samvat||592–593|
|- Kali Yuga||3771–3772|
|Minguo calendar||1241 before ROC|
|Seleucid era||982/983 AG|
|Thai solar calendar||1213–1214|
797 or 416 or −356
— to —
798 or 417 or −355
Year 671 (DCLXXI) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. The denomination 671 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.
- Perctarit returns from exile and reclaims his realm, which is being ruled on behalf of Garibald, since his father King Grimoald I died. He deposes the young king, and becomes the new ruler of the Lombard Kingdom in Italy. During his reign Perctarit makes Catholicism the official religion, but does not recognize papal authority. Grimoald is buried in the St. Ambrogio Church (Milan).
- Battle of Two Rivers: King Ecgfrith of Northumbria defeats the Picts under King Drest VI, in the vicinity of Moncreiffe Island, near Perth (Scotland). After the battle the Picts are reduced to slavery, and subject to the yoke of captivity for the next 14 years.
- Yijing, Chinese Buddhist monk, travels by boat from Guangzhou, and visits the capital of the partly Buddhist kingdom of Srivijaya in Palembang (Indonesia). He stays for 6 months to study Sanskrit grammar and the Malay language.
- June 10 – Emperor Tenji introduces a water clock (clepsydra) called Rokoku. The instrument, which measures time and indicates hours, is placed in the capital of Ōtsu in Japan.
- Silla seizes control of the former Baekje capital of Sabi from the Tang Protectorate General to Pacify the East.
- Sigebert IV, Frankish prince (approximate date)
- F. Espenak (2009). "Annular Solar Eclipse of 0671 Dec 07" (PDF). NASA. Retrieved May 29, 2015.
- Brown, T. S. The New Cambridge Medieval History: II. c. 700 - c. 900. p. 321.
- Fraser, James E. (2006). "The Pictish Conquest", p.59
- Colgrave, Bertram (1927). "The Life of Bishop Wilfrid", Cambridge University. ISBN 978-0521-31387-2
- "Why is June 10 known as Time Memorial Day?". Seiko Institute of Horology. Archived from the original on February 12, 2012. Retrieved April 17, 2012.