Swedish royalty, who reigned as king from 12 February 1771 until his death on 29 March 1792. A patron of the arts and benefactor of arts and literature, Gustav founded several academies, among them the Swedish Academy, created a national costume and had the Royal Swedish Opera built.
He was the eldest son of King Adolph Frederick and Queen Louise Ulrika, who was a sister of Frederick the Great, King of Prussia.
He seized power from the government in a coup d’état in 1772, ending the Age of Liberty and venturing into a campaign to restore royal autocracy. This was completed by the Union and Security Act in 1789, sweeping away most of the last pretences of Riksdag rule. As a bulwark of enlightened despotism, he spent considerable public funds on cultural ventures: this contributed among his critics to controversy about his reign. Attempts to seize Norway with Russian assistance, and then to recapture the Baltic provinces by a war against Russia, were unsuccessful, although much of Sweden’s former military might was restored.
An admirer of Voltaire, Gustav legalized Catholic and Jewish presence in the realm and enacted wide-ranging reforms aimed at economic liberalism, social reform and the abolition, in many cases, of torture and capital punishment.
By proxy in Christiansborg Palace, Copenhagen, on 1 October 1766 and in person in Stockholm on 4 November 1766, Gustav married Princess Sophia Magdalena, daughter of King Frederick V of Denmark. The match was not a happy one, but it produced two children: Crown Prince Gustav Adolf (1778–1837), and Prince Carl Gustav, Duke of Småland (1782–1783). It was rumored at the time that Gustav was homosexual. The close personal relationships which he formed with two of his courtiers, Count Axel von Fersen and Baron Gustav Armfelt, were alluded to in that regard.
Following the French Revolution, Gustav pursued an alliance of monarchs aimed at crushing the insurrection and reinstating his French counterpart, Louis XVI, offering Swedish assistance to the royal cause in France under his leadership. He was mortally wounded by a gunshot in the lower back during a masquerade ball, as part of a noblist-parliamentary coup attempt, but managed to assume command and quell the uprising before succumbing to septicemia 13 days later, a period during which he received apologies from many of his political enemies.

Link to Wikipedia biography