|Ab urbe condita||1978|
|Balinese saka calendar||1146–1147|
|English Regnal year||9 Hen. 3 – 10 Hen. 3|
|Chinese calendar||甲申年 (Wood Monkey)|
3921 or 3861
— to —
乙酉年 (Wood Rooster)
3922 or 3862
|- Vikram Samvat||1281–1282|
|- Shaka Samvat||1146–1147|
|- Kali Yuga||4325–4326|
|Japanese calendar||Gennin 2 / Karoku 1|
|Minguo calendar||687 before ROC|
|Thai solar calendar||1767–1768|
1351 or 970 or 198
— to —
1352 or 971 or 199
|Wikimedia Commons has media related to 1225.|
- The Teutonic Knights are expelled from Transylvania, because they wanted to separate from Hungary.
- The Magna Carta is reaffirmed (for the third time) by Henry III of England, in return for issuing a property tax.
- Iltutmish, the sultan of Delhi, repels a Mongol attack and marches against Ghiyasuddin, who cedes Bihar to him.
- July 27 – Visby Cathedral in Sweden is consecrated.
- December 31 – Lý Chiêu Hoàng, the only empress regnant in the history of Vietnam, marries Trần Thái Tông, making him the first emperor of the Trần Dynasty, at age seven.
- Thomas Aquinas, Italian theologian (d. 1274)
- Saint Isabelle of France, French princess, daughter of Louis VIII of France
- David VI Narin, King of Georgia (d. 1293)
- Michael VIII Palaiologos, Byzantine Emperor (d. 1282)
- Chabi, chief wife of Kublai Khan and granddaughter in law of Genghis Khan (d. 1281) (Approximate date)
- February 18 – Hugh Bigod, 3rd Earl of Norfolk (b. 1186)
- August 16 – Hōjō Masako, Japanese regent and onna-bugeisha, "female warrior" (b. 1156)
- October 5 – Al-Nasir, Abbasid caliph in Baghdad
- October 28 – Jien, Japanese poet and historian (b. 1155)
- November 7 – Engelbert II of Berg, Archbishop of Cologne
- date unknown