Danish slave trade occurred separately in two different periods. During the Viking Age, thralls (Norse slaves) were an important part of the economy and one of the main reasons for the raids on England where slaves where capture. This practice was abolished after the Denmark became Christan. Trade with black slaves as part of the transatlantic slave trade was started by Denmark-Norway around 1671, when the Danish West India Company was chartered, to 1802, when the Dano-Norwegian regent Prince Frederick carried out a ban on the country's participation in the trade. As of 1778, it was estimated that the Dano-Norwegians were shipping about 3,000 Africans to the Danish West Indies for enslavement yearly. The country's ships transported approximately 100,000 enslaved Africans, about 2% of the total number the early 19th century.