King Gustavus IV (1778–1837) was arrested and forced to abdicate by his generals with his uncle, the duke of Sudermania, assuming control as regent. The king had been pro-British but the new regime promptly made peace with Russia and Denmark and excluded Britain from its ports.
See Franklin L. Ford, A General History of Europe 1780-1830 (London: Longman, 1970), p. 215.