1288

By place

Europe

• War on [Gotland 1288|A civil war] breaks out on Gotland between the burghers of Visby and the rural farmers of Gotland; while the exact reason for this war is unknown, the most likely reason is the construction of a large wall around Visby, and the introduction of a toll, which the farmers were forced to pay.
• June 5 - War of the Limburg Succession - Battle of Worringen: Brabantian forces under Duke John I defeat the coalition army of Cologne, Luxemburg, and Nassau at Worringen. John liberates the city of Cologne from rule by the Electorate of Cologne, which has previously been one of the major ecclesiastical principalities of the Holy Roman Empire.
• Summer - Sultan Muhammad II drives the rebellious Banu Ashqilula from one stronghold to the next, where they are finally expelled from Granadan territory in Al-Andalus. Meanwhile, Muhammad manages through diplomatic intrigue, to turn the Castilian aristocracy against King Sancho IV. In response, King Alfonso III proclaims the 18-year-old Alfonso de la Cerda as ruler of Castile and León.
• August 8 - Pope Nicholas IV proclaims a crusade against the 26-year-old King Ladislaus IV, who had lost credibility by favoring his semi-pagan Cuman subjects in Hungary, and in general refusing to conform to the social standards of Western Europe. Meanwhile, the Hungarian government loses more power because the clergy and most of the nobles rule the kingdom independently.
• October 28 - Treaty of Canfranc: King Edward I signs an agreement with Alfonso III at Canfranc, about the release of Charles II, who has been captured by Admiral Roger of Lauria in the Battle of the Gulf of Naples.

England and Scotland

• January 20 - Newcastle Emlyn Castle in West Wales is recaptured by the English forces after a ten-day siege, bringing Rhys ap Maredudd's revolt to an end. Rhys is exiled to Ireland.
• The Parliament of Scotland creates a law allowing women to propose marriage to men during leap years; men who refuse such proposals are required to pay a fine to the spurned bride-to-be.

Levant

• Spring - Genoa orders Admiral Benedetto Zaccaria to send five galleys to support Genoese suzerainty of Tripoli. Princess Lucia, sister of the late Count Bohemond VII, arrives in Acre, where the Knights Hospitaller escort her to the frontier with Tripoli. The commune refuses to accept her as new ruler and places the city under Genoese protection. After negotiations, Lucia offers to confirm Genoa's existing commercial privileges in Tripoli.

Asia

• April 9 - Battle of Bạch Đằng: Đại Việt general Trần Hưng Đạo sinks the fleet of an invading Mongol-led Yuan expeditionary army. He orders the placing of steel-tipped bamboo stakes in the Bach Dang River near Ha Long Bay. This ends the intentions of Kublai Khan to conquer Vietnam and Champa.
• April - The Japanese era Kōan ends and the Shōō era begins during the reign of the 22-year-old Emperor Fushimi.

By topic

Art and culture

• The oldest surviving bell, in the clocks atop the dome of St. Peter's Basilica in Rome, is built.
• Work is begun on the construction of Mob Quad in Merton College, Oxford.

Markets

• June 16 - Petrus, bishop of Västerås, buys 1/8 of the Stora Kopparberg copper mine in Falun, Sweden. During the reign of King Magnus Ladulås, nobles and foreign merchants from Lübeck take interests in the mining area.
• The Flemish city of Ghent seeks rights to start redeeming its already issued annuities. It is a clear indication of financial difficulty, and maybe an early sign of the crisis of the 13th Century.

Religion

• February 22 - Nicholas IV is elected as the successor of the late Honorius IV during a conclave in Rome and becomes the 191st pope of the Catholic Church.
• March-April - Rabban Bar Sauma, Chinese Nestorian monk and diplomat, arrives at Rome and is received by Nicholas IV, who gives him communion on Palm Sunday.

Technology

• The oldest-known bronze handgun in the world is dated to this year, a Chinese gun found in Acheng District, that was once used to suppress the rebellion of the Mongol prince Nayan.