No record has survived about ancient kings of Finland, but Finland has repeatedly been part of monarchical states as a sub-unit of a monarchy based outside Finland proper. After the 13th century Swedish conquest, Finland was a part of the Kingdom of Sweden and occasionally a usually nominal Duchy, with some brief feudalistic characteristics in the 16th century. Elevation of status to Grand Duchy in 1581 had no effect on the stately position.
King Charles IX briefly used "King of Finns" (Finnars...Konung) as part of his official titulary during 1607-1611. The change in the title had no impact on the official status of Finns or Finland.
In 1742, following the Russian occupation of Finland in the Russo-Swedish War (1741–1743) and vague promises of making the country independent, the four estates gathered in Turku and decided to ask the Empress Elisabeth if the then Duke Peter of Holstein-Gottorp, great-nephew of the late king Charles XII of Sweden, could be proclaimed as the King of Finland. However, the political situation had soon outgrown the idea of Finnish independence, and it quickly evaporated.
Following the capture of Finland from Sweden by Russia in 1809, Finland kept the Swedish constitution formally intact and became an autonomous region within the Russian Empire under the title of Grand Duchy of Finland. The Russian Emperor wielded the powers reserved for the king as the Grand Duke of Finland, creatively applying the autocratic Swedish constitution of 1772 and 1789. Interestingly, the first Grand Duke Alexander I was the grandson of the said Peter, who had ascended the imperial throne in 1762.
In December 1917, Finland declared her independence from Russia, as a reaction to the October Revolution in Russia. The internal unrest in the country soon declined into an open civil war, won by the White side, i.e. the non-socialist parties. During the war, the White side was heavily supported by Germany. In an effort to cement the alliance with Germany, the Finnish parliament, purged of socialist members, elected Prince Frederick Charles of Hesse as the King of Finland. Before Frederick Charles could move to Finland, the collapse of the Central Powers made the idea of German-born Finnish king untenable and he renounced the throne. After new elections, the Parliament, now with representatives of all parties, adopted a republican constitution in 1919 which has been in effect ever since, with major modification in 1999.
Today, there are no known monarchist movements in Finland nor any pretenders to any of the earlier planned or actual positions of Dukes, Grand Dukes or Kings of Finland.
However there is a potential pretender: Prince Philipp of Hesse, who, nonetheless, sees the idea of his pretension as ridiculous and refrains from making any claim to the Finnish "throne".