|Ab urbe condita||1968|
|Balinese saka calendar||1136–1137|
|English Regnal year||16 Joh. 1 – 17 Joh. 1|
|Chinese calendar||甲戌年 (Wood Dog)|
3911 or 3851
— to —
乙亥年 (Wood Pig)
3912 or 3852
|- Vikram Samvat||1271–1272|
|- Shaka Samvat||1136–1137|
|- Kali Yuga||4315–4316|
|Japanese calendar||Kenpō 3|
|Minguo calendar||697 before ROC|
|Thai solar calendar||1757–1758|
1341 or 960 or 188
— to —
1342 or 961 or 189
|Wikimedia Commons has media related to 1215.|
- March 4 – King John of England makes an oath to Pope Innocent III as a crusader, to gain his support.
- May 31 – Mongol conquest of the Jin dynasty: after the long Battle of Zhongdu, Genghis Khan's Mongols capture and torch Beijing (the city burns for more than a month).
- June 15 – King John of England is forced, by rebellious barons of England at Runnymede, to put the Great Seal of the Realm on a set of articles confirming their rights and those of the towns and Church, and confirming the status of trial by jury, which on June 19 is confirmed as Magna Carta.
- August – King John of England rejects Magna Carta, leading to the First Barons' War.
- August 24 – Pope Innocent III declares Magna Carta invalid.
- November 11 – The Fourth Council of the Lateran gathers in Rome under Pope Innocent III, who adopts the title "Vicar of Christ".
- December – First Barons' War: Alexander II of Scotland invades northern England.
- Otto IV, Holy Roman Emperor, is excommunicated and forced to abdicate as Emperor and King of Burgundy, replaced by Frederick II (King of the Romans 1212–1250).
- The Dominican Order is founded, according to some sources.
- Bhiksu Ananda of Kapitanagar completes writing the holy Buddhist book Arya Astasahasrika Prajnaparamita (sutra), in gold ink in Ranjana script.
- 1215–1216 – The Macy Jug, from Iran, is made. It is now kept at The Metropolitan Museum of Art, New York.
- Kalinga Magha, from Kalinga Province in India, lands in Sri Lanka with a force of 24,000 men, to capture the city of Polonnaruwa and depose its king, Parakrama Pandya.
- September 23 – Kublai Khan, 6th Khagan of the Mongol Empire and Genghis Khan's grandson, founder of the Yuan dynasty (d. 1294)
- date unknown
- approximately – Douceline of Digne, French beguin (d. 1274)
- possible – Pope John XXI (d. 1277)
- February 3 (or February 4) – Eustace, Bishop of Ely and former Lord Chancellor of England
- July 2 – Eisai, Japanese Buddhist priest (b. 1141)
- September 1 – Otto, bishop of Utrecht
- December 21 – Ali ibn Muhammad ibn al-Walid, Dāʿī al-Muṭlaq of Tayyibi Isma'ilism (b. c. 1128)
- date unknown – Bertran de Born, French soldier and troubadour
- Esclarmonde of Foix, French Cathar
- approximately – Margaret of Beverley, Christian pilgrim (b. c. 1150)
- Williams, Hywel (2005). Cassell's Chronology of World History. London: Weidenfeld & Nicolson. pp. 133–135. ISBN 0-304-35730-8.
- Palmer, Alan; Veronica (1992). The Chronology of British History. London: Century Ltd. pp. 77–79. ISBN 0-7126-5616-2.
- Poonawala, Ismail K. (2009). "ʿAlī b. al-Walīd". In Fleet, Kate; Krämer, Gudrun; Matringe, Denis; Nawas, John; Rowson, Everett (eds.). Encyclopaedia of Islam, THREE. Brill Online. ISSN 1873-9830.