Year 1455 (MCDLV) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar.
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 was a dramatic reversal when, in 1537 the bull Sublimis Deus of Pope Paul III, forbade 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 Earl of Douglas.
May 22 – First Battle of St Albans: Richard, Duke of York, defeats and captures King Henry VI of England.
July – Siege of Berat.
January 9 – William IV, Duke of Jülich-Berg, Count of Ravensberg (1475–1511) (d. 1511)
February 2 – King John of Denmark, Norway, and Sweden (d. 1513)
February 22 – Johann Reuchlin, German-born humanist, scholar of Greek and Hebrew (d. 1522)
March 3
King John II of Portugal (d. 1495)
Ascanio Sforza, Catholic cardinal (d. 1505)
March 15 – Pietro Accolti, Italian Catholic cardinal (d. 1532)
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 – Deposed Queen Lady Yun, Korean Queen (d. 1482)
August 2 – John Cicero, Elector of Brandenburg (d. 1499)
August 15 – George, Duke of Bavaria (d. 1503)
November 9 – Johann V of Nassau-Vianden-Dietz, Lord of Breda and 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)
Nicholas Barnham, Knight, killed in the War of the Roses (d. 1485)
February 18 – Fra Angelico, Italian painter (b. 1395)
March 24 – Pope Nicholas V (b. 1397)
April 1 – Zbigniew Oleśnicki, Polish 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
December 1 – Lorenzo Ghiberti, Italian sculptor and metal smith (b. 1378)
December 2 – Isabel of Coimbra, queen of Portugal (b. 1432)
1455 Wikipedia (Text) CC BY-SA