The County of the Castle of Vyborg
The Swedish started to build the castle of Vyborg during the third crusade to secure the eastern border of their conquest. The Swedish administrative system was spread to the territory; the County of the castle of Vyborg was formed to be its foundation and it supervised the tax collection, the legal proceedings and the missionwork by the Catholic church. The County of the castle of Vyborg streched from Kymijoki to Rajajoki and from the Gulf of Finland to the hunting country north of Mikkeli. In 1539 the territory became smaller at the foundation of the County of the castle of Savonlinna.
The body of local administration then consisted of medieval counties of castles which were divided into bailiwicks in the 1540s. They centered around royal estates. In the 16th century there were ten counties of castle - though the tenth, that is: the county of the castle of Kakisalmi only between the years 1581 and 1595. The number of the bailiwicks varied according to administrative arrangements.
Information on the population in Karelia during the Swedish rule is available from the 1540s, when land registers started to be created due to the taxation reform based on written accountancy system effectuated by Gustavus of Vasa. A more coherent file on population based on tax lists can be made since the 1560s. The county administration was formed in the Constitution of 1634, when a county replaced the former bailiwick as the basical fiscal unit. The account books of the bailiwick time of administration are called bailiwick accounts and those of the county administration are called county accounts.
Census lists started to be kept in 1634, and all the persons who had paid poll-tax were marked in them. In 1656 the persons under 15 or over 63 years of age who did not cultivate land were exempted from paying the poll-tax. These age limits remained in force for over two centuries, for in 1865 the lower age limit was raised by one year.