The 1280s is the decade starting January 1, 1280 and ending December 31, 1289.
Europe in the 1280s was marked by naval warfare on the Mediterranean and consolidation of power by the major states. Ongoing struggles over the control of Sicily provoked lengthy naval warfare: after the Sicilian Vespers rebellion, the French Angevins struggled against Aragon for control of the island. King Rudolph I of Germany established the Habsburg dynasty in Austria when he invested his two sons with power there. In England, King Edward I of England completed the conquest of Wales and annexed the territory via the Statute of Rhuddlan; he also constructed a series of castles in Wales to suppress any future rebellions. Edward I also established several important legal traditions, including a court system to hear claims on the king's behalf and a codification of the separation of church and state legal powers. The death of King Alexander III of Scotland fomented political wrangling in Scotland which would soon lead to increased English influence over Scotland. In Sweden, King Magnus I of Sweden founded a Swedish nobility.
1288 – 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.
1281 – August 15 – The second Mongol invasion of Japan is foiled at the Battle of Kōan (or Battle of Hakata Bay) as a large typhoon — famously called a kamikaze, or divine wind — destroys much of the combined Chinese and Korean fleet and forces, numbering over 140,000 men and 4,000 ships.
1284 – Mamluk sultan of Egypt Qalawun signs a ten-year truce with the Crusader city of Acre; he will violate the truce on pretexts in 1290.
1285 – April 25 – Mamluk sultan Qalawun begins a siege of the Crusader fortress of Margat (in present-day Syria), a major stronghold of the Knights Hospitaller thought to be impregnable; he captures the fortress a month later.
1287 – Mamluk sultan Qalawun captures the port city of Latakia in present-day Syria.