February 13, 1503 – Disfida di Barletta – famous challenge between 13 Italian and 13 French knights near Barletta.

April 28, 1503 – The Battle of Cerignola is fought. It is noted as the first battle in history won by small arms fire using gunpowder.

May 10, 1503 – Christopher Columbus visits the Cayman Islands and names them Las Tortugas after the numerous turtles there.

May 28, 1503 – James IV of Scotland and Margaret Tudor are married according to a Papal Bull by Pope Alexander VI. A Treaty of Everlasting Peace between Scotland and England signed on that occasion results in a peace that lasts ten years.

August 8, 1503 – King James IV of Scotland marries Margaret Tudor, daughter of King Henry VII of England at Holyrood Abbey, Edinburgh, Scotland.

January 11, 1503 – Parmigianino, Italian artist (d. 1540)

March 22, 1503 – Antonio Francesco Grazzini, Italian writer (d. 1583)

June 1, 1503 – Wilhelm von Grumbach, German adventurer (d. 1567)

June 28, 1503 – Giovanni della Casa, Italian poet (d. 1556)

June 30, 1503 – John Frederick, Elector of Saxony (d. 1554)

July 23, 1503 – Anne of Bohemia and Hungary, Queen consort of Ferdinand I, Holy Roman Emperor (d. 1547)

August 12, 1503 – King Christian III of Denmark and Norway (d. 1559)

October 23, 1503 – Isabella of Portugal, queen of Spain and empress of Germany (d. 1539)

November 17, 1503 – Agnolo di Cosimo, Italian painter (d. 1572)

December 14, 1503 – Nostradamus, French astrologer (d. 1566)