Birkarls (birkarlar in Swedish, unhistorical pirkkamiehet or pirkkalaiset in Finnish; bircharlaboa, bergcharl etc. in historical sources) were a small, unofficially organized group that controlled taxing and commerce in central Lappmarken in Sweden during the 13th to 17th centuries.
Birkarls (bircharlaboa) are first mentioned in 1328, when they are listed as one of the settler groups in northern Hälsingland that covered the western coast of Gulf of Bothnia all the way up and around the gulf to Oulu River.
Origin of the name birkarl is probably in an ancient Scandinavian word birk that has been used in reference to commerce in various contexts.
In the late 16th century, claims about birkarls coming from Great Pirkkala (a parish in Upper Satakunta) emerged, propagated by birkarls themselves in their battle to prevent the state from stripping their privileges. This is at least partly true, since men from Pirkkala appear as witnesses in a document from 1374 about local borders in northern Pohjanmaa. Later in the 19th century a Finnish term pirkkamiehet or pirkkalaiset was invented as a "domestic" name for birkarls. It never appears in any of the documentation or traditions, but is commonly used in Finland today to mean birkarls.
In total, some 20 theories are estimated to exist to explain the origin and name of the birkarls.
The main purpose of the birkarl organization was to control the trade with Sami people and tax them. Sami people were traditionally taxed by Norwegians already in the Viking Age or even earlier. Later Russians started to tax them as well. After having southern Finland under control around 1250, Sweden became interested in the situation in the north. Eventually, some Sami people paid taxes to all three states. Birkarls were just one element in the colonial system taking benefit of the Sami area.