• The ninth and final crusade comes to an end as Saracen Turks led by Mamluk sultan of Egypt Khalil capture and sack Acre, the last and most important Crusader stronghold in the Holy Land, destroying the Latin Kingdom of Jerusalem and effectively shattering Crusader power in the region.
• Three independent mountain communities, Unterwalden, Schwyz, and Uri, unite against Hapsburg encroachment as the League of Forest Cantons, forming the nucleus of what will become the independent nation of Switzerland.
• Scottish nobles grudgingly recognize the authority of English king Edward I in exchange for his mediation of the succession crisis created by the death of Scottish king Alexander III in 1286.
• Pope Nicholas IV issues a papal bull confirming the independence of San Marino.
• Castilian king Sancho IV reconquers Tarifa from the Moors.
• The glassmakers of Venice are forced to move to the island of Murano in order to contain the risk of fire, establishing the a famous glass industry that would one day supply most of Europe's mirrors and chandeliers.
• The artificial Kunming Lake, later to become the site of the Qing Summer Palace, is constructed to the north of Beijing as a reservoir by famous engineer and astronomer Guo Shoujing.
• Japanese emperor Kameyama establishes the great Buddhist temple of Nanzenji in Kyoto.
• Dante pens a poem, later collected in La Vita Nuova, in which he first mentions Beatrice, the great love of his life.

These people were born in 1291:

• Pierre Roger, the future Pope Clement VI.
• Portuguese king Alfonso IV.
• Hungarian king Charles Robert.
• Influential French composer Philippe de Vitry.
• Can Francesco della Scala, lord of Verona, the greatest lord of the Ghibelline family that ruled Verona from 1277 to 1387, and one of Dante's patrons.
• Theodore I, Marquis of Montferrat.
• Aimone the Peaceful, Count of Savoy.

These people died in 1291:

• Rudolf I, German king and first member of the Hapsburg dynasty.
• Persian poet Sa'di, still considered the national poet of Iran.
• Arghun Khan, fourth Mongol ruler of the Ilkhanate in what is now Iran, succeeded by his dissolute brother Gaikhatu Khan.
• Sa'ad al'Da'ulah, Jewish grand vizier to Arghun Khan, assassinated by political enemies following Arghun's death.
• Eleanor of Provence, strong-minded queen to English king Henry III.
• Korean born Chinese general Hong Dagu.
• Aragonese king Alfonso III.

1290 - 1291 - 1292

13th century