1455

January–December

• 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.
• July 14 – Thirteen Years' War: a decisive victory of the Teutonic Order during the Battle for Kneiphof.
• 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.

• January 9 – William IV, Duke of Jülich-Berg, Count of Ravensberg (d. 1511)
• January 29 – Johann Reuchlin, German-born humanist and scholar (d. 1522)
• February 2 – King John of Denmark, Norway, and Sweden (d. 1513)
• March 3
  • King John II of Portugal (d. 1495)
  • Ascanio Sforza, Italian Catholic cardinal (d. 1505)
• March 15 – Pietro Accolti, Italian Catholic cardinal (d. 1532)
• April 17 – Andrea Gritti, Doge of Venice (d. 1538)
• May 16 – Wolfgang I of Oettingen, German count (d. 1522)
• June 1 – Anne of Savoy, Savoy royal (d. 1480)
• July 9 – Frederick IV of Baden, Dutch bishop (d. 1517)
• July 15 – Queen Yun, Korean queen (d. 1482)
• August 2 – John Cicero, Elector of Brandenburg (d. 1499)
• August 15 – George, Duke of Bavaria (d. 1503)
• November 9 – John V, Count of Nassau-Siegen, Stadtholder of Guelders and Zutphen (d. 1516)
• date unknown
  • Peter Vischer the Elder, German sculptor (approximate date) (d. 1529)
  • Estefania Carròs i de Mur, Spanish educator (approximate date) (d. 1511)
  • Raden Patah, Javanese sultan, founder of the Demak Sultanate (d. 1518)
  • María de Ajofrín, Spanish visionary (d. 1489)
  • Nicholas Barnham, English knight, killed in the War of the Roses (d. 1485)
  • Angelo da Vallombrosa, Italian jurist and abbot (d. 1530)

• February 18 – Fra Angelico, Italian painter (b. 1395)
• March 24 – Pope Nicholas V (b. 1397)
• April 1 – Zbigniew Oleśnicki, Polish Catholic cardinal and statesman (b. 1389)
• May 1 – Archibald Douglas, Earl of Moray (in battle)
• May 22 (killed at the First Battle of St Albans):
  • Henry Percy, 2nd Earl of Northumberland, Lancastrian commander (b. 1393)
  • Edmund Beaufort, 2nd Duke of Somerset, Lancastrian commander (b. 1406)
  • Thomas Clifford, 8th Baron de Clifford, Lancastrian commander (b. 1414)
• September 3 – Alonso Tostado, Spanish Catholic bishop
• October 22 – Johannes Brassart, Flemish composer
• October 28 – Guillaume-Hugues d'Estaing, French Catholic cardinal
• December 1 – Lorenzo Ghiberti, Italian sculptor and metal smith (b. 1378)
• December 2 – Isabel of Coimbra, queen of Portugal (b. 1432)