An independent Swedish state emerged during the early 12th century. After the Black Death in the middle of the 14th century killed about a third of the Scandinavian population, the Hanseatic League threatened Scandinavia's culture, finances and languages.[dubious – discuss] This led to the forming of the Scandinavian Kalmar Union in 1397, which Sweden left in 1523. When Sweden became involved in the Thirty Years War on the Reformist side, an expansion of its territories began and eventually the Swedish Empire was formed. This became one of the great powers of Europe until the early 18th century. Swedish territories outside the Scandinavian Peninsula were gradually lost during the 18th and 19th centuries, ending with the annexation of present-day Finland by Russia in 1809. The last war in which Sweden was directly involved was in 1814, when Norway was militarily forced into personal union. Since then, Sweden has been at peace, maintaining an official policy of neutrality in foreign affairs. The union with Norway was peacefully dissolved in 1905. Sweden was formally neutral through both world wars and the Cold War, albeit Sweden has since 2009 openly moved towards cooperation with NATO.
The name Sweden was loaned from Dutch in the 17th century to refer to Sweden as an emerging great power. Before Sweden's imperial expansion, Early Modern English used Swedeland. Sweden is derived through back-formation from Old English Swēoþēod, which meant "people of the Swedes" (Old NorseSvíþjóð, LatinSuetidi). This word is derived from Sweon/Sweonas (Old Norse Sviar, Latin Suiones). The Swedish name Sverige (a compound of the words Svea and rike, with lenition of the consonant [k], first recorded in the cognate Swēorice in Beowulf) literally means "realm of the Swedes", excluding the Geats in Götaland.
Variations of the name Sweden are used in most languages, with the exception of Danish and Norwegian using Sverige, FaroeseSvøríki, IcelandicSvíþjóð, and the more notable exception of some Finnic languages where Ruotsi (Finnish) and Rootsi (Estonian) are used, names commonly considered as referring to the people from the coastal areas of Roslagen, Uppland, who were known as the Rus', and through them etymologically related to the English name for Russia.
The etymology of Swedes, and thus Sweden, is generally not agreed upon but may derive from Proto-GermanicSwihoniz meaning "one's own", referring to one's own Germanic tribe.