The 1450s decade ran from January 1, 1450, to December 31, 1459.
- February 7 – John de la Pole, 2nd Duke of Suffolk, marries Lady Margaret Beaufort.
- February 26 – Francesco Sforza enters Milan after a siege, becoming Duke of the city-state and, founding a dynasty that will rule Milan for a century.
- March – French troops under Guy de Richemont besiege the English commander in France, Edmund Beaufort, 1st Duke of Somerset, in Caen.
- April 15 – Battle of Formigny: French troops under the Comte de Clermont defeat an English army under Sir Thomas Kyriel and Sir Matthew Gough, which was attempting to relieve Caen.
- May 8 – Jack Cade's Rebellion: Kentishmen revolt against King Henry VI of England.
- May 9 – Abdal-Latif Mirza, a Timurid dynasty monarch, is assassinated.
- May 13 – Charles VIII of Sweden, also serving as Carl I of Norway, is declared deposed from the latter throne, in favor of Christian I of Denmark.
- June 18 – Battle of Seven Oaks: Jack Cade's rebels are driven from London by loyal troops, bringing about the collapse of the rebellion.
- July 6 – Caen surrenders to the French.
- July 12 – Jack Cade is slain in a skirmish.
- August 12 – Cherbourg, the last English territory in Normandy, surrenders to the French.
- October 5 – Jews are expelled from Lower Bavaria, by order of Duke Ludwig IX.
- November 3 – The University of Barcelona is founded.
- November 23 – First Siege of Krujë: Albanian troops are victorious, forcing an Ottoman army of approximately 100,000 men to retreat from Albania.
- February – Alexăndrel retakes the throne of Moldavia, in his long struggle with Petru Aron.
- February 22 – William Douglas, 8th Earl of Douglas is killed by James II of Scotland, at Stirling Castle.
- March 17 – Reconquista – Battle of Los Alporchones (around the city of Lorca in Murcia): The combined forces of the Kingdom of Castile, and its subsidiary kingdom of Murcia, defeat the Emirate of Granada.
- March 19 – Frederick III, Holy Roman Emperor, becomes the last to be crowned in Rome.
- May 31 – Revolt of Ghent: Philip the Good, Duke of Burgundy, officially declares war on Ghent.
- June 18 – Pope Nicholas V issues the bull Dum Diversas, legitimising the colonial slave trade.
- January 8 – Pope Nicholas V publishes Romanus Pontifex, an encyclical addressed to King Afonso V of Portugal, which sanctions the conquest of non-Christian lands, and the reduction of native non-Christian populations to 'perpetual slavery' (later there will be a dramatic reversal when, in 1537, the bull Sublimis Deus of Pope Paul III forbids the enslavement of non-Christians).
- February 23 – The Gutenberg Bible is the first book printed with movable type.
- April 8 – Pope Calixtus III succeeds Pope Nicholas V, as the 209th pope.
- Spring – The Wars of the Roses begin in England.
- May 1 – Battle of Arkinholm: Forces loyal to King James II of Scotland defeat the supporters of the Earl of Douglas.
- May 22 – First Battle of St Albans: Richard, Duke of York, defeats and captures King Henry VI of England.
- November 15 – The conflict between Vladislav II of Wallachia and John Hunyadi escalates, so the latter decides to support Vlad the Impaler for the throne of Wallachia, the following year.
- February 11 – After years of captivity and absence from the Ming throne, the Zhengtong Emperor of China is reinstated, as the Tianshun Emperor.
- February 24 – Charles VIII of Sweden is declared deposed. The Archbishop of Sweden, Jöns Bengtsson Oxenstierna, and statesman Erik Axelsson Tott become co-regents of Sweden. The throne is then offered to Christian I of Denmark and Norway.
- March 6 – King James II of Scotland decrees that “. . . ye futebawe and ye golf be uterly cryt done and not usyt . . “ The first historical mention of the game of golf.
- April 12 – Ştefan cel Mare secures the throne of Moldavia, which he retains for the next 47 years.
- June 23 – Christian I is elected king of Sweden, ending the war between Sweden and Denmark and restoring the Kalmar Union.
- August 14 – The Mainz Psalter, the second major book printed with movable type in the West, the first to be wholly finished mechanically (including colour), and the first to carry a printed date, is printed for the Elector of Mainz.
- September 2 – Battle of Ujëbardha: One of Skanderbeg's most important victories is won against the Ottoman army, in the open field.