View source for 1288

==== 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.<ref>{{Cite book |last=Starbäck |first=Carl Georg |url=https://books.google.com/books?id=xNJJAQAAMAAJ&dq=slaget+vid+h%C3%B6gebro&pg=PA489 |title=Berättelser ur svenska historien: Sagoåldern. Medeltiden I., till Kalmare-unionen |date=1885 |publisher=F. & G. Beijers |language=sv}}</ref><ref>{{Cite web |title=Inbördeskriget 1288 |url=https://www.guteinfo.com/?id=1899 |access-date=2025-02-02 |website=www.guteinfo.com}}</ref>
* [[June 5]] &ndash; [[War of the Limburg Succession]] &ndash; [[Battle of Worringen]]: Brabantian forces under Duke [[John I, Duke of Brabant|John I]] defeat the coalition army of [[Electorate of Cologne|Cologne]], [[County of Luxemburg|Luxemburg]], and [[Duchy of Nassau|Nassau]] at [[Worringen]] (in a struggle to conquer the [[Duchy of Limburg]]). 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]].<ref>Boffa, S. 2004. Warfare in medieval Brabant: 1356–1406. Coll.: "Warfare in History", Boydell Press, Woodbridge, UK, p. 289.</ref>
* Summer &ndash; Sultan [[Muhammad II of Granada|Muhammad II]] drives the rebellious [[Banu Ashqilula]] from one stronghold to the next, where they are finally expelled from Granadan territory in [[Al-Andalus]] (modern [[Spain]]). Meanwhile, Muhammad manages through diplomatic intrigue, to turn the Castilian aristocracy against King [[Sancho IV of Castile|Sancho IV]]. In response, King [[Alfonso III of Aragon|Alfonso III]] proclaims the 18-year-old [[Alfonso de la Cerda]] as ruler of [[Kingdom of Castile|Castile]] and [[Kingdom of León|León]].<ref>Joseph F. O'Callaghan (2011). ''The Gibraltar Crusade: Castile and the Battle for the Strait'', pp. 95–96. {{ISBN|978-0-8122-2302-6}}.</ref>
* [[August 8]] &ndash; Pope [[Pope Nicholas IV|Nicholas IV]] proclaims a crusade against the 26-year-old King [[Ladislaus IV of Hungary|Ladislaus IV]], who had lost credibility by favoring his semi-pagan Cuman subjects in [[Kingdom of Hungary (1000–1301)|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.<ref>Engel, Pál (2001). ''The Realm of St. Stephen: A History of Medieval Hungary, 895–1526'', p. 109. Tauris Publishers. {{ISBN|1-86064-061-3}}.</ref><ref>Kontler, László (1999). ''Millennium in Central Europe: A History of Hungary'', p. 84. Atlantisz Publishing House. {{ISBN|963-9165-37-9}}.</ref>
* [[October 28]] &ndash; [[Treaty of Canfranc]]: King [[Edward I of England|Edward I]] signs an agreement with Alfonso III at [[Canfranc]], about the release of [[Charles II of Naples|Charles II]], who has been captured by Admiral [[Roger of Lauria]] in the [[Battle of the Gulf of Naples]] (see [[1284]]).<ref>Runciman, Steven (1958). ''The Sicilian Vespers: A History of the Mediterranean World in the Later Thirteenth Century'', p. 246. Cambridge University Press. {{ISBN|978-1-107-60474-2}}.</ref>