Gustav IV Adolf or Gustav IV Adolph was King of Sweden from 1792 until he was deposed in a coup in 1809. He was also the last Swedish monarch to be the ruler of Finland.

The 1809 Instrument of Government, adopted on 6 June 1809 by the Riksdag of the Estates and King Charles XIII, was the constitution of the Kingdom of Sweden from 1809 to the end of 1974. It came about as a result of the Coup of 1809, in which King Gustav IV Adolf was deposed. The promulgation of the constitution marks the point at which Sweden transitioned from the absolute monarchy of the Gustavian era into a stable, constitutional monarchy adhering to the rule of law and significant civil liberties.