The 1290s was a decade of the Julian Calendar which began on January 1, 1290, and ended on December 31, 1299.
- Year without winter – Exceptionally rare instance of uninterrupted transition, from autumn 1289 to the following spring, in Britain and mainland western Europe.
- March 1 – The University of Coimbra is founded in Lisbon, Portugal by King Denis of Portugal; it moves to Coimbra in 1308.
- July 10 – Ladislaus IV of Hungary is assassinated by three Cumans (Árbóc, Törtel and Kemence), at the castle of Körösszeg (modern-day Cheresig) in Romania.
- July 18 – By the Edict of Expulsion, King Edward I of England orders all Jews (at this time probably numbering around 2,000) to leave England by November 1 (All Saints' Day); on the Hebrew calendar this is Tisha B'Av, a day that commemorates many calamities.
- July 23 – Andrew III of Hungary is crowned in Székesfehérvár by Lodomer, Archbishop of Esztergom, having escaped from captivity in Vienna.
- August 1 – The country of Wallachia is founded (traditional date).
- December – The twelve Eleanor crosses are erected between Lincolnshire and London in England, as King Edward I mourns the death of his queen consort, Eleanor of Castile.
- December 18 – Upon the death of Magnus III, he is succeeded by his 10-year-old son Birger as king of Sweden. Although Sweden is an elective monarchy at this time, Birger has been appointed heir to the throne already in 1284.
- Construction of Llandaff Cathedral is completed in Cardiff, Wales, 170 years after it was begun.
- The Mongol Golden Horde invades the Bessarabia region of Moldavia.
- The second of the Statutes of Mortmain are passed under King Edward I of England, which prevents land from passing into possession of the church. The statute Quia Emptores is also passed, reforming the feudal system of land leases, and allowing the sale of fee simple estates.
- King Denis of Portugal decrees that Portuguese is the official language of Portugal, replacing classical Latin in that capacity.
- Construction on the Akershus Fortress of Oslo, Norway is begun.
- Spring – Vandino and Ugolino Vivaldi set sail from Genoa with the goal of reaching India; they never return.
- May 10 – Scottish nobles recognize the authority of King Edward I of England, in mediating the resolution of the succession crisis, created by the death of King Alexander III of Scotland, five years earlier.
- August – The Swiss Confederation is formed by Uri, Schwyz, and Unterwalden (the "three forest cantons"), at Rütli, by the Federal Charter.
- Sancho IV of Castile captures Tarifa from the Moors.
- The Habsburgs acquire the Swiss city of Lucerne.
- Pope Nicholas IV confirms the independence of San Marino, via papal bull.
- All glassmakers in Venice are forced to move to the island of Murano, in order to contain the risk of fire, thus establishing the glass industry there.
- Klenová Castle is constructed in southern Bohemia, as part of a frontier defense system.
- King Andrew III of Hungary gives royal town privileges to Bratislava, the present-day capital of Slovakia.
- April 5 – The Papal election, 1292–94 begins.
- November 17 (Julian calendar) – John Balliol is selected by King Edward I of England as King of Scotland, from among 13 competitors for the Crown of Scotland; Edward then treats John as a puppet ruler and Scotland as a vassal state, eventually provoking the Wars of Scottish Independence, commencing in 1296.
- King Mangrai the Great of Ngoenyang conquers and annexes the Mon kingdom of Hariphunchai, creating a political union in the form of the Lanna Kingdom.
- The Vaghela Dynasty in Gujarat is subjugated by the Deccan Yadava Dynasty of Daulatabad.
- The Mamluk sultan of Egypt, Al-Ashraf Khalil, invades the Armenian Kingdom of Cilicia.
- The Isfendiyarid Dynasty is founded in the Kastamonu Province.
- The Mongols land on Java, taking the capital, but it proves impossible to hold.
- The Taxatio Ecclesiastica, compiled in 1291–92, is completed under the order of Pope Nicholas IV.
- December – Mamluk sultan of Egypt Khalil is assassinated by his regent Baydara, who briefly claims the sultanate, before being assassinated himself by a rival political faction.
Arts and culture
- July 5 – Following the Papal election, 1292–94, Pope Celestine V succeeds Nicholas IV, becoming the 192nd pope.
- Autumn – In response to the actions of new royal administrators in north and west Wales, Madog ap Llywelyn leads a revolt against his English overlords.
- December 24 – Pope Boniface VIII succeeds Pope Celestine V, becoming the 193rd pope, after Celestine V abdicates the papacy on December 13, only five months after reluctantly accepting his surprise election on July 5, wishing to return to his life as an ascetic hermit.
- John Balliol, King of Scotland, decides to refuse King Edward I of England's demands for support in a planned invasion of France, the result being the negotiation of the Auld Alliance with France and Norway in the following year. These actions play a part in precipitating the Scottish Wars of Independence, which begin in 1296.
- Strata Florida Abbey is rebuilt; it had been destroyed some years earlier, during King Edward I of England's conquest of Wales.
- Architect Arnolfo di Cambio designs Florence Cathedral (Cattedrale di Santa Maria del Fiore, better known simply as Il Duomo); he also begins work on the Basilica of Santa Croce, Florence.
- England and Portugal enter into the first iteration of the Anglo-Portuguese Alliance, the oldest alliance in the world still in force.
- Edward I of England and Philip the Fair of France declare war on each other. To finance this war, both kings lay taxes on the clergy. Pope Boniface VIII insists that kings gain papal consent for taxation of the clergy, and forbids churchmen to pay taxes.
- The foreign creditors of the Sienese Gran Tavola Bank start demanding their deposits back, thus accelerating the liquidity crisis faced by the firm.
- February 24 – Alauddin Khalji, sultan of Delhi, sends his generals Ulugh Khan and Nusrat Khan to conquer Gujarat.
- May 10 – Kyawswa of Pagan and Crown Prince Theingapati are executed at Myinsaing, by the three brothers of the Myinsaing Kingdom (nominally Kyawswa's viceroys), as traitors for submitting to the Mongol Empire.
- July 27 – Osman I declares his Anatolian beylik (principality) to be independent of the Seljuq Dynasty Sultanate of Rum, originating the Ottoman Empire, with Söğüt as the original capital, which will last until the 1920s.
- A Mongol khan launches a campaign into India with 200,000 men, but Alauddin Khalji, sultan of Delhi, defeats them.
- The Kingdom of Singapura is founded by a fleeing Srivijayan prince (it will last for almost 100 years).
- The city of Florence bans the use of Arabic numerals for commerce, allowing only Roman numerals.