Swedish rule ended in 1721 in most of so-called Old Finland, the south-eastern part of the Finnish territories, as a result of the Great Northern War.

In colonised coastal areas the Finnish population, remaining as a minority, principally lost its fishing and cultivation rights to the colonists.

In fact, it remained a widely accepted view in Sweden proper that the Finns were in principle a separate and conquered people and therefore not necessarily entitled to be treated equitably with Swedes.

The Finnish language, dating from prehistoric times, and some parts of folklore religion and culture remained under Swedish rule, even though they changed as they adapted to new circumstances.

According to historical sources, the reason for the crusades besides spreading Catholic faith, were the numerous raids that Finnish tribes made to Sweden.

[17][18] By the 14th century, with the successful crusades and the partial colonization of Finnish coastline with Christian Swedish colonists, what is now Western and Southern Finland and the Karelian isthmus, had become part of Sweden, Catholic Church and the Uppsala diocese.

In medieval times, the historical regions of Finland Proper and Satakunta were part of the central area of the Swedish government and retained the ties to Scandinavia they had formed already during prehistory.

In Southwest Finland, Tavastia, southern Karelia there was permanent agricultural population, which gradually condensed and spread to a larger area.

With his active foreign policy, the king Eric of Pomerania ran into conflict with the Hanseatic League, which made trade more difficult.

The opposition to the upper class caused by the minor peasant rebel movements in Finland can be explained by the expansion of the property of the crown and the frälse.

In the same autumn, the bishop Magnus II Tavast and Krister Nilsson arrived in Sweden, and in the negotiations there they participated in the discharge of the leaders of the Engelbrekt Engelbrektsson rebellion and the forming of a compromise.

In order to fight the rebel movements, the Finnish peasants were promised a cut in taxes in a letter dated 24 June 1436, signed by the archbishop, the drots and the marshal, under authority from the government.

Seppo Suvanto [fi; sv] has interpreted this so that Sweden feared that the Finnish local government would detach itself from the Swedish realm and the Finns would choose a leader of their own.

After Christopher died in 1448, Charles VIII sailed from Vyborg to Stockholm with 800 armed men, where he was elected king (1448 to 1457), apparently because of his military superiority.

In the late 16th century, the Danish went on pillages on the Finnish coast, and the pirate captain Otto Rudi robbed Turku and its cathedral's treasures.

The Finnish-born brothers Erik and Ivar Fleming conquered the Finnish castles for Gustav Vasa and drove the Danish away from Finland in 1523.

In the 1530s, Gustav Vasa started to bring in German government officials to the country, along with whom new visions of royal power arrived in Sweden.

During the 1544 Västerås Diet [fi; sv], the royalty was changed to hereditary and Gustav Vasa's eldest son Erik was named heir to the throne.

Despite the interim peace, guerilla warfare continued on both sides of the eastern border, which led to Kainuu and Northern Ostrobothnia being largely deserted in the 1580s.

The question of the monarchy was entwined with church politics: in the time of the counter-reformation in Europe Sigismund was a Catholic, which made his position even more problematic in Lutheran Sweden.

According to the Law of Moses, witchcraft and magic was forbidden, and for example blasphemy, swearing, betraying one's parents, perjury, killing, demanding too high interest, false testimony and numerous sexual crimes could be punished by death.

According to current research, the reasons for the rebellion included strain left from the 25-year war, financial setbacks and suffering caused by the castle camp system.

[30] During the Great Northern War, professor Israel Nesselius [fi; sv] of the Turku Academy wrote several articles about the fate of the Finnish language.

The Swedish official and economist Ulrik Rudenschöld [fi; sv] specified in 1738 that this kind of migration would help develop bilingualism in the eastern parts of the realm.

Jakob Faggot continued the same thought in his letter in 1745, but according to him, the Finnish people should be taught Swedish so they could become as good Swedes in their language as they were in their mind.

The Russian empress Elizabeth spread a manifesto in 1742, urging Finns to abandon Sweden and form an autonomous state protected by Russia.

[37] Of the researchers, Eino Jutikkala says: "People in various regions and of various estates in Finland in the late 18th century consciously considered themselves as Finnish as opposed to the Swedish who lived on the other side of the sea.

In Carl av Forsell's [sv] official examinations of Finland and Sweden, he found high literacy an essential part of religious education for commoners in both countries in 1833.

The last Grand Duke of Finland during the Swedish era was Gustav IV Adolf's second son Karl Gustaf, who was born in 1802 and died as an infant in 1805.

Some bitterness in Sweden remained in the hope of regaining Finland in a war with Russia, but the idea of Scandinavism or Scandinavian unification like in Germany and Italy started to develop among the Nordic language-speaking populations in Scandinavia in the 19th century.