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On January 5, 1968, reformist Alexander Dubček was elected First Secretary of the Communist Party of Czechoslovakia, beginning the Prague Spring — a period of political liberalisation that sought to create "socialism with a human face". The reform was crushed on August 21, 1968 by the Soviet invasion. Dubček was deposed and the country reverted to orthodox communism.

On January 5, 1925, theoretical physicist Chien-Shiung Wu was born in Berlin — known as the "First Lady of Physics". Her experiments demonstrated that parity is not conserved in weak interactions, confirming a theory by Lee and Yang that won the Nobel Prize in 1957, though Wu, whose work was essential, was excluded from the award in one of the Nobel committee's greatest oversights.

On January 5, 1477, the army of Charles the Bold, Duke of Burgundy, was crushed at the Battle of Nancy by the troops of the Duke of Lorraine, and Charles himself was killed in the fighting. His death without male heirs precipitated the Burgundian crisis and the gradual absorption of Burgundian territories by France and the Habsburgs, redrawing the map of western Europe.