and fishing, the minority Mountain Sámi continued to hunt wild reindeer. Around 1500, they started to tame these animals into herding groups, becoming the well-known reindeer nomads, often portrayed by outsiders as following the traditional Sámi lifestyle. The Mountain Sámi had to pay taxes to three states, Norway, Sweden and Russia, as they crossed each border while following the annual reindeer migrations; this caused much resentment over the years. Between 1635 and 1659, the Swedish crown forced Swedish conscripts and Sámi cart drivers to work in the Nasa silver mine, causing many Sámis to emigrate from the area to avoid forced labour. As a result, the population of Pite- and Lule-speaking Sámi decreased greatly. Post-1800s For long periods of time, the Sámi lifestyle thrived because of its adaptation to the Arctic environment. Indeed, throughout the 18th century, as Norwegians of Northern Norway suffered from low fish prices and consequent depopulation, the Sámi cultural element was strengthened, since the Sámi were mostly independent of supplies from Southern Norway. During the 19th century, the pressure of Christianization of the Sámi increased, with some Sámi adopting Laestadianism. With the introduction of seven compulsory years of school in 1889, the Sámi language and traditional way of life came increasingly under pressure from forced cultural normalization. Strong economic development of the north also ensued, giving Norwegian culture and language higher status. On the Swedish and Finnish sides, the authorities were less militant, although the Sámi language was forbidden in schools and strong economic development in the north led to weakened cultural and economic status for the Sámi. From 1913 to 1920, the Swedish race-segregation political movement created a race-based biological institute that collected research material from living people and graves. Throughout history, Swedish settlers were encouraged to move to the northern regions through incentives such as land and water rights, tax allowances, and military exemptions. The strongest pressure took place from around 1900 to 1940, when Norway invested considerable money and effort to assimilate Sámi culture. Anyone who wanted to buy or lease state lands for agriculture in Finnmark had to prove knowledge of the Norwegian language and had to register with a Norwegian name. This caused the dislocation of Sámi people in the 1920s, which increased the gap between local Sámi groups (something still present today) that sometimes has the character of an internal Sámi ethnic conflict. In 1913, the Norwegian parliament passed a