Duke of Finland

In the late 15th century, historian Ericus Olai claimed that Bishop Kol of Linköping (died about 1196) had been the Duke of Finland (Dux Finlandiae).

However, some historians date the small Stenberga Castle in Masku to the late 12th century,[2] when the Novgorodian wars reached Finland and may have resulted in a temporary Swedish military presence in the area.

Bengt's appointment ended a 35-year-long period of episcopal rule in Finland, effective since the Second Swedish Crusade around 1249.

With his second wife Ingeborg of Norway, Duke Valdemar had a son, born in 1316, who is assumed to have died as a child.

Lord Bengt Algotsson (1330–60), accused for political reasons by Saint Bridget of being a homosexual lover of King Magnus IV of Sweden (nephew of Duke Valdemar above), had already in 1353 been recognized as Duke of Halland, originally a Danish principality, and in 1353 or 1354 also was given the Duchy of Finland.

The Duke apparently never seriously attempted to establish himself as ruler of Finland, being satisfied to bear revenues from the duchy.

In 1556, two hundred years after it was vacated by the removal of Duke Bengt Algotsson, King Gustav I of Sweden (reigned 1523–1560) gave the Duchy of Finland to his second son, the then 18-year-old Prince John (1537–1592).

Additionally, John was appointed Governor-General of Finland, including all the other areas beyond the Gulf of Bothnia and up to the eastern border.

After the death of his father, John ran his own foreign policy which at times was at odds with his elder brother King Eric XIV of Sweden (reigned 1560–1568).

In domestic affairs too, John soon opposed the King, together with a party of high nobility who all were against an increasing centralization of the government.

In 1589 he appears to have made arrangements to grant the Duchy of Finland at birth to his younger son Duke John (see below).

In 1581, King John III additionally assumed the subsidiary title of Grand Prince of Finland and Karelia.