The Curonians or Kurs (Curonian: Kursi; German: Kuren; Latvian: kurši; Russian: курши; Lithuanian: kuršiai; Estonian: kuralased; Polish: Kurowie) were a Baltic tribe living on the shores of the Baltic Sea in what are now the western parts of Latvia and Lithuania from the 5th to the 16th centuries, when they merged with other Baltic tribes. They gave their name to the region of Courland (Kurzeme), and they spoke the Old Curonian language. Curonian lands were conquered by the Livonian Order in 1266 and they eventually merged with other Baltic tribes participating in the ethnogenesis of Lithuanians and Latvians. Direct descendants of the Curonians include the Kuršininkai of the Curonian Spit and the so-called Curonian Kings of Courland.
The Curonians were known as fierce warriors, excellent sailors and pirates. They were involved in several wars and alliances with Swedish, Danish and Icelandic Vikings. During that period they were the most restless and the richest of all the Balts.
In c. 750, according to Norna-Gests þáttr saga from c. 1157, Sigurd Ring, a legendary king of Denmark and Sweden, fought against the invading Curonians and Kvænir in the southern part of what today is Sweden: