Birkarls (birkarlar in Swedish, unhistorical pirkkamiehet or pirkkalaiset in Finnish; bircharlaboa, bergcharl etc. in historical sources) were a small Finnish group that controlled taxing and commerce in the area of northern Scandinavia from the 13th century to the early 17th century, and possibly already before 13th century as well. 
According to Professor Jouko Vahtola, the most probable assumption is that the Birkarls were originally Finnish traders. Vahtola suggests that a big part of the Birkarls had originated from the historical Tavastia area, located in southern Finland. In the latter half of the 13th century, King Magnus III Birgersson is traditionally claimed to have granted the privileges for the Birkarls (Kven traders) to control the trade and taxes in the north. This may have been just a ratification of an already existing condition.
In 1328, Tälje Charter ("Tälje stadga") mention the Birkarls ("bircharlaboa"). Based on the information revealed, the Birkarls then inhabited areas e.g. in northern Hälsingland, which covered the western coast of the Gulf of Bothnia, and from there all the way up and around the gulf to Oulu River. Tälje Charter is a state treaty, in which the king of Sweden guarantees the Kvens (Birkarls) trading rights in the north (a translation from Latin last printed in 1995 - Wallerström, page 48). 
In the late 16th century, claims about the Birkarls originating from Great Pirkkala (a parish in Upper Satakunta) emerged, propagated by the Birkarls themselves in their battle to prevent the state from stripping their privileges. This claim 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 the Birkarls. The term is commonly used in Finland today in reference to Birkarls.
In total, some 20 theories are estimated to exist to explain the origin and name of the Birkarls.
Sami trade and taxation monopoly
The main purpose of the Birkarl organization was to control the trade with the Sami people and to tax them. According to medieval accounts and some other evidence, the Sami were taxed by the Norsemen and the Finnic tribe of the ancient Kvens during the Viking Age, but presumably already before Viking Age as well. During Viking Age - and possibly long before -, the Finnic Karelians too participated in the taxing of the Sami.
By the late Middle Ages, both the slowly expanding Realm of Sweden and Novgorod too had become more interested in the taxation of the Sami in the north. However, the status of the Birkarls in control of the Sami taxation remained strong up-til the mid-16th-century, after which the Birkarls were just one element in the colonial system taking benefit of the Sami area. In the early 17th century, the Birkarls fully lost their upper hand in the battle for the rights to tax the Sami people.
No pre-14th-century documents have survived, where the granting of rights to the Birkarls for the taxation and trade monopoly in the north could be viewed. However - despite of the lack of documentation -, the post-Viking-Age newly-born country of Sweden clearly appears to have been forced to tolerate and/or support the situation for centuries.
From the first half of the 14th century, a related document has survived. It is the signing of a state treaty between Sweden and the Birkarls, known as Tälje Charter ("Tälje stadga" in Swedish). In that treaty, the king of Sweden guaranteed the Kvens ("birkarls") trading rights in the north (translation from Latin last printed in 1995, Wallerström, page 48). 
In practice, a Birkarl owned the Sami people on his turf, and they were treated as if they were property. Privileges to own Sami people usually went in the family. Later, the Birkarl privileges became merchandise as well. 
Area of influence
Birkarls were active in northern Scandinavia and Fennoscandia, but particularly on the western and northern coastal areas of the Gulf of Bothnia. In the final centuries of their activity, their influence was felt strongest in and around the Tornio, Luleå and Piteå river valleys, each of the valleys forming a separate area known as "Lappmark", with its own Birkarls. Sami people south of Piteå were the so-called "Crown Samis", who paid their taxes directly to the king. The area of Tornio is known as the most important center for the Birkarl activities in history.
Birkarls living on their area of influence were very few, totaling only about 50 men still in the early 16th century.
According to Professor Emeritus Kyösti Julku, there are at least 12 prehistoric Kven place names in the modern-day area of Troms in Northern Norway. In his 1539 map of Scandinavia named Carta Marina, Olaus Magnus marks Birkarl Kvens ("Berkara Qvenar") inhabiting the area roughly between the modern-day city of Tromsø and the archipelago of Lofoten in Norway. The first ever recorded Norwegian tax records from the mid-1500s onward also mention Kvens, suggesting the presence of the Birkarls in Norway at the time. These tax records are stored at the National Archival Services of Norway (Riksarkivet). 
In the east, the Kemi River Valley was at least partly under the influence of the Birkarls still in the late 16th century.
Decline and end
Birkarls remained powerful operators in north as long as the Swedish state's hold there was weak. After the disintegration of the Union of Kalmar in the early 16th century, the status of the Birkarls gradually changed. A major setback for the Birkals took place in 1553, when King Gustav Vasa terminated their right to tax the Sami people.
Birkarls' trade monopoly was now turned to gradual decline, and from 1570s onward it was seriously set in the line of fire. Unable to continue their former lives as usual, many Birkarls became local tax authorities (lapinvouti in Finnish). However, still in the 1590s the Birkarls tried to hold on to - or regain - tax control of the Sea Sami people on the coastal areas of the Arctic Ocean.
At this point, the state of Sweden had become interested in concentrating the trading in the north into towns which were relatively easy to control. This soon changed the former role of the Birkarls as the controllers of the northern trade and taxation. Having no longer official status on these fields, the Birkarl organization had little means to fight back, and it silently eroded away in the 17th century, after administrative changes initiated by King Charles IX.
In 1607, once King Charles IX had strengthened his hold on the crown of Sweden, he appended to it the title 'King of the Caijaners' (people of Kainuu), apparently using the title the first time on March 16, 1607. However, Kainuu (same as Kvenland, according to Kyösti Julku) "occupied a separate position from the rest of Finland for a long time to come". 
Tornio, Luleå and Piteå all received their town charters in 1621, marking an "official" end to the period of strong influence of the Birkarls in all of northern Scandinavia and Finland.
The ancient Kven people and their land called Kvenland are discussed in the c. 890 AD Old English version by King Alfred of Wessex of the world history written originally by the Romano-Hispanic author Orosius. Also medieval Icelandic accounts written in the 12th and 13th centuries discuss the Kvens and their nation called Kvenland, which was ruled by kings.
It is often speculated that what became known as Birkarls would in fact have been post-Viking-Age upper class members of the Kven society discussed in medieval accounts. According to this assumption, the area where the Birkarls operated, would have located in the heartland of the ancient Kvenland.
As a name for a country, Kvenland seems to have gone out of ordinary usage around the end of the Viking Age, unrecognized by scholars by the 14th century. As the first ever account written in Swedish language, Eric's Chronicle, was published as late as the 14th century, no medieval references to "Kvenland" or "Kvens" are available from Swedish literature.
However, in the 1539 map Carta Marina by the Swedish author Olaus Magnus, the Birkarl Kvens ("Berkara Qvenar") are shown inhabiting the Norwegian North Atlantic coast, roughly in the middle in between the archipelago of Lofoten and the modern-day city of Tromsø. In his 1555 publication Historia de Gentibus Septentrionalibus ("A Description of the Northern Peoples"), Magnus also mentions both terms: The Finnish traders that commuted between and inhabited the general area of Tornio and the modern-day area of Norway are told to have been called "Kvens". 
Historians consider it likely, that for the medieval inhabitants of the modern-day area of Norway the term Kven included Birkarl traders. Whatever the case, most of the Kven minority in the present-day northern Norway originates from - or has immigrated from - the same area on which Birkarls were active.
The flag of Kvenland was lifted up at the Kiruna City Hall in Sweden on March 16, 2013, at 11:00, in celebration and honor of the first annual Day of the Kvens. Hereafter, the day is meant to be recognized wider in the Kven communities of the north, and by others as well.
The date for the occasion was chosen from the 14th century signing of a state treaty between Sweden and Kvenland, known as Tälje Charter ("Tälje stadga" in Swedish). In that treaty, the king of Sweden guaranteed the Kvens ("Birkarls") trading rights in the north (translation from Latin last printed in 1995, Wallerström, page 48). 
The city of Kiruna is a part of the Kiruna Municipality. It is the northernmost municipality of Sweden, and geographically it is Sweden's largest, covering roughly 4.604% of the total area of Sweden.
In the past, the Kven language spoken in Norway was considered a dialect of Finnish language, much like the Finnic Meänkieli language in northern Sweden. Today, both are officially recognized minority languages in the areas where the languages are spoken. The Finnish, Meänkieli and Sami all are officially recognized minority languages in the Kiruna Municipality in Sweden.
- Tornionlaakson historia I. Birkarlit, 'pirkkalaiset'. Malungs boktryckeri AB. Malung, Sweden. 1991. The article draws heavily from the material available in the book.
- Tälje stadga (Translation from Latin). Wallerström, 1995. Sweden.
- Kyösti Julku: Kvenland - Kainuunmaa. With English summary: The Ancient territory of Kainuu. Oulu, 1986.
- Klinge, Matti. Muinaisuutemme merivallat (1983). Book is in Finnish, also published in Swedish as Östersjövärlden (1984) and in English as Ancient Powers of the Baltic Sea (2006).