The attempt to create a Kingdom of Finland in 1742 is a little-known chapter in the history of Finland. Following the Russian occupation in the Russo-Swedish War (1741–1743) and vague promises of making the country independent, Finns elected the then Duke Peter of Holstein-Gottorp (who later became heir to the throne of Russia and tsar as Peter III) as the King of Finland. However, the political situation had outgrown the idea of Finnish independence and it quickly evaporated.
Duke Charles Peter of Holstein-Gottorp was the closest living relative (great-nephew) and the natural heir of the recently deceased, childless Queen Ulrika Eleonora (died 1741), and similarly the great-nephew of the childless King Charles XII of Sweden, Ulrika Eleonora's only brother and predecessor on the throne. Even though he was just a 14-year-old Scandinavian German who had never even been to Sweden, he was very popular among the peasantry, in Finland especially for the fact that he was also the nephew of Empress Elizabeth of Russia and could thus ensure a more enduring peace.
It has been described of Charles Peter of Gottorp that he identified himself with his Swedish heritage and that even afterwards, living in St. Petersburg, would have liked to make his own environment and lands to resemble Scandinavia. In the imperial court of St. Petersburg, he grew up in a specifically "Holsteinian" separate sub-culture.
When the Russian counter-offensive started in March 1742, Chancellor Bestuzhev probably toyed with the idea of making a buffer state in between Sweden and Russia. Tsarina Elizabeth presented Finns — then still a part of the Kingdom of Sweden — with a declaration (Manifest of Empress Elisabeth to Finnish People) wherein she promised to make Finland independent if they did not resist her troops.
By July 1742, Russia had occupied all of Finland, meeting almost no resistance at all due to ineffective Swedish military command and forces, and that month a group of Finnish peasants pleaded with the Russians to make the duke the King of Sweden.