|Ab urbe condita||1995|
|Balinese saka calendar||1163–1164|
|English Regnal year||26 Hen. 3 – 27 Hen. 3|
|Chinese calendar||辛丑年 (Metal Ox)|
3938 or 3878
— to —
壬寅年 (Water Tiger)
3939 or 3879
|- Vikram Samvat||1298–1299|
|- Shaka Samvat||1163–1164|
|- Kali Yuga||4342–4343|
|Japanese calendar||Ninji 3|
|Minguo calendar||670 before ROC|
|Thai solar calendar||1784–1785|
1368 or 987 or 215
— to —
1369 or 988 or 216
|Wikimedia Commons has media related to 1242.|
- In Maghrib, after a string of successes against the fast declining Almohads, Abu Zakariya, the first Hafsid ruler of Ifriqiya, conquers the Kingdom of Tlemcen.
- Emperor Go-Saga ascends to the throne of Japan.
- Batu Khan establishes the Golden Horde at Sarai.
- The Mongols invade the Seljuk Sultanate.
- April 5 – During a battle on the ice of Lake Peipus, Russian forces, led by Alexander Nevsky, rebuff an invasion attempt by the Teutonic Knights.
- Cleves, Germany is chartered as a city.
- Kiel, Germany is chartered as a town.
- The Archbishop of Mainz conquers the city of Wiesbaden, from the House of Nassau.
- King Sancho II of Portugal conquers the cities of Tavira, Alvor and Paderne, in his continuing effort against the Muslims, known as Reconquista.
- Mongol invasions
- German colonists arrive in Bratislava, after the Mongols fail to conquer the city.
- The Mongols of the Golden Horde devastate Volga Bulgaria, and force the nation to pay tribute.
- A French goldsmith working in Budapest, named Guillaume Boucher, is captured by the Mongols and taken to Karakorum.
- The Golden Bull is issued by King Béla IV to inhabitants of Gradec (today's Zagreb) and Samobor in Croatia, during the Mongol invasion of Europe. By this golden bull King Bela IV proclaim a free royal city.
- Battle of Grobnicko Polje: Croats stop the Mongolian invasion.
- Timeline of medicine and medical technology: Ibn Nafis suggests that the right and left ventricles of the heart are separate, and describes the lesser circulation of blood.
- The diocese of Warmia, Poland is created.
- July 24 – Blessed Christina von Stommeln, German Roman Catholic mystic, ecstatic, and stigmatic (d. 1312)
- December 15 – Prince Munetaka, Japanese shōgun (d. 1274)
- date unknown
- February 10
- March 26 – William de Forz, 3rd Earl of Albemarle
- July 14 – Hōjō Yasutoki, regent of Japan (b. 1183)
- October 7 – Emperor Juntoku of Japan (b. 1197)
- December 9 – Richard le Gras, Lord Keeper of England and Abbot of Evesham
- date unknown
- Gilbert Meynier (2010) L'Algérie cœur du Maghreb classique. De l'ouverture islamo-arabe au repli (658-1518). Paris: La Découverte; pp.38.
- Picard, Christophe (2000). Le Portugal musulman (VIIIe-XIIIe siècle. L'Occident d'al-Andalus sous domination islamique. Paris: Maisonneuve & Larose. p. 110. ISBN 2-7068-1398-9.