born Jan. 24, 1746, Stockholm, Swed.
died March 29, 1792, Stockholm
King of Sweden (1771–92).
The son of King Adolf Frederick (1710–71), he succeeded to a weakened Swedish throne. Unable to mediate between the contending factions of the Riksdag (legislature), in 1772 he established a new constitution that increased the crown's power. He introduced numerous enlightened reforms, which antagonized the nobility. He waged an unpopular war on Russia (1788–90), and when a group of Swedish officers mutinied, he again augmented royal authority in a new constitution (1789). Gustav planned to form a league of European monarchs to oppose the French Revolution, but the Swedish nobility remained opposed to him and had him assassinated. Gustav was a patron of the arts and a playwright, and his reign was known as the Swedish enlightenment.