June 5 – John I of Brabant defeats the duchy of Guelders in the Battle of Worringen — one of the largest battles in Europe of the Middle Ages — thus winning possession of the duchy of Limburg. The battle also liberates the city of Cologne from rule by the Archbishopric of Cologne; it had previously been one of the major ecclesiastical principalities of the Holy Roman Empire.
August 8 – Pope Nicholas IV proclaims a crusade against King Ladislaus IV of Hungary, who had lost credibility by favoring his semi-pagan Cuman subjects and in general refusing to conform to the social standards of western Europe.
The Scots Parliament 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.
Vietnamese general Tran Hung Dao sinks the entire fleet of an invading Yuan dynastyMongol army by placing steel-tipped bamboo stakes in the Bach Dang River, near Halong Bay.