1213 (MCCXIII) was a common year starting on Tuesday of the Julian calendar, the 1213th year of the Common Era (CE) and Anno Domini (AD) designations, the 213th year of the 2nd millennium, the 13th year of the 13th century, and the 4th year of the 1210s decade.
|Centuries:||12th century – 13th century – 14th century|
|Decades:||1180s 1190s 1200s – 1210s – 1220s 1230s 1240s|
|Years:||1210 1211 1212 – 1213 – 1214 1215 1216|
|Ab urbe condita||1966|
|Balinese saka calendar||1134–1135|
|English Regnal year||14 Joh. 1 – 15 Joh. 1|
|Chinese calendar||壬申年 (Water Monkey)|
3909 or 3849
— to —
癸酉年 (Water Rooster)
3910 or 3850
|- Vikram Samvat||1269–1270|
|- Shaka Samvat||1134–1135|
|- Kali Yuga||4313–4314|
|Japanese calendar||Kenryaku 3 / Kenpō 1|
|Minguo calendar||699 before ROC|
|Thai solar calendar||1755–1756|
1339 or 958 or 186
— to —
1340 or 959 or 187
- May 30 – Battle of Damme; English fleet under William Longsword destroyes a French fleet off the Belgian port in the first major victory for the fledgling Royal Navy.
- September 12 – Battle of Muret; The Toulousain and Aragonese forces of Raymond VI of Toulouse and Peter II of Aragon defeated by the Albigensian Crusade under Simon de Montfort
- Jin China is overrun by Mongols under Genghis Khan, who plunder the countryside and cities, until only Beijing remained free, despite two bloody palace coups and a lengthy siege.
- Pope Innocent III issues a charter, calling for the Fifth Crusade to recapture Jerusalem.
- September 12 – King Peter II of Aragon (killed in battle) (born 1174)
- September 24 – Gertrude of Merania, wife of Andrew II of Hungary (murdered) (born 1185)
- October 10 – Frederick II, Duke of Lorraine
- Dowsprunk, Grand Prince of Lithuania
- Geoffrey Fitz Peter, 1st Earl of Essex
- Sharafeddin Tusi, Persian mathematician (born 1135)