|Centuries:||16th century – 17th century – 18th century|
|Decades:||1630s 1640s 1650s – 1660s – 1670s 1680s 1690s|
|Years:||1665 1666 1667 – 1668 – 1669 1670 1671|
|1668 by topic:|
|Arts and Science|
|Architecture - Art - Literature - Music - Science|
|Lists of leaders|
|Colonial governors - State leaders|
|Birth and death categories|
|Births - Deaths|
|Establishments and disestablishments categories|
|Establishments - Disestablishments|
|Ab urbe condita||2421|
|English Regnal year||19 Cha. 2 – 20 Cha. 2|
|Chinese calendar||丁未年 (Fire Goat)
4364 or 4304
— to —
戊申年 (Earth Monkey)
4365 or 4305
|- Vikram Samvat||1724–1725|
|- Shaka Samvat||1590–1591|
|- Kali Yuga||4769–4770|
|Japanese calendar||Kanbun 7
|Julian calendar||Gregorian minus 10 days|
|Minguo calendar||244 before ROC
|Thai solar calendar||2210–2211|
|Wikimedia Commons has media related to 1668.|
1668 (MDCLXVIII) was a leap year starting on Sunday (dominical letter AG) of the Gregorian calendar and a leap year starting on Wednesday (dominical letter ED) of the Julian calendar, the 1668th year of the Common Era (CE) and Anno Domini (AD) designations, the 668th year of the 2nd millennium, the 68th year of the 17th century, and the 9th year of the 1660s decade. As of the start of 1668, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1918.
- January – The Triple Alliance of 1668 is formed between England, Sweden and the United Provinces.
- February 13 – In Lisbon, a peace treaty is established between Afonso VI of Portugal and Carlos II of Spain, by mediation of Charles II of England, where the legitimacy of the Portuguese monarch is recognized. Portugal yields Ceuta to Spain.
- May 2 – The first Treaty of Aix-la-Chapelle ends the War of Devolution.
- July 7 – Bishop Isaac Barrow founds the Bishop Barrow Trust to establish a university on the Isle of Man (King William's College).
- Mid-July – Henry Morgan sacks Portobello and Panama City; the lack of booty from the latter attack leads to the city being burned.
- September 9 – Molière's comedy, L'Avare, is first performed.
- The British East India Company takes over Bombay.
- The first National Bank in Europe (the Riksbank) is founded in Stockholm, Sweden.
- Emperor Yohannes I of Ethiopia convenes a church council in Gondar, which decides to expel all Roman Catholics in Ethiopia.
- Isaac Newton builds the first reflecting telescope (Newton's reflector).
- April 20 – Yuri Troubetzkoy, Governor of Belgorod (d. 1739)
- May 8 – Alain-René Lesage, French writer (d. 1747)
- June 23 – Giambattista Vico, Italian philosopher and historian (d. 1744)
- July 21 – Frederick Heinrich of Saxe-Zeitz-Pegau-Neustadt (d. 1713)
- September 8 – Giorgio Baglivi, Armenian doctor and writer (d. 1707)
- October 18 – John George IV, Elector of Saxony (d. 1694)
- October 30 – Sophia Charlotte of Hanover, sister of King George I of Great Britain (d. 1705)
- November 10
- November 11 – Johann Albert Fabricius, German scholar (d. 1736)
- November 27 – Henri François d'Aguesseau, Chancellor of France (d. 1751)
- November 30 – William August, Duke of Saxe-Eisenach (d. 1671)
- December 11 – Apostolo Zeno, Italian poet and journalist (d. 1750)
- December 31 – Herman Boerhaave, Dutch humanist and physician (d. 1738)
- January 6 – Luis de Benavides Carrillo, Marquis of Caracena (b. 1608)
- February 8 – Alessandro Tiarini, painter (b. 1577)
- February 21 – John Thurloe, English Puritan spy (b. 1616)
- March 16 – Francis Talbot, 11th Earl of Shrewsbury (b. 1623)
- April 21 – Jan Boeckhorst, Flemish painter (b. c. 1604)
- May 21 – Christoph Delphicus zu Dohna, soldier and diplomat (b. 1628)
- June 20 – Heinrich Roth, German Sanskrit scholar (b. 1620)
- September 16
- September 19 – Sir William Waller, English Civil War general (b. c. 1635)
- November 17 – Joseph Alleine, English non-conformist preacher (b. 1634)
- November 21 – Adolf William, Duke of Saxe-Eisenach (b. 1632)
- December 14 – Charles Berkeley, 2nd Viscount Fitzhardinge, English politician (b. 1599)
- Journal of Manx Museum. Accessed 28 August 2014
- Isaac Newton: adventurer in thought, by Alfred Rupert Hall, page 67