Curonians have been mentioned in numerous Viking sagas as participants in numerous battles on Swedish soil, including the legendary battle of Brávellir on the side of the Swedish against the Danes. Sometimes Curonians would even make alliances with Icelandic and Swedish Vikings, however, they would most often collaborate with another nearby raider folk - the Oesellians of Estonian Saaremaa in raids against them.
Curonians had also been theorized to have taken part in the Pillage of Sigtuna (1187) near modern Stockholm, which was one of the most important cities of Sweden at the time.
Sources also mention Curonian settlements to have existed in Danish Bornholm, Swedish Gotland and even Eastern Sweden itself, showing the far reaching and powerful influence of Baltic Curonians. One could argue this tradition of Curonian colonisation would be continued by the German-led Duchy of Courland in the 1600s, with the Duchy establishing its own colonial settlements in the Caribbean and West Africa, becoming one of the fastest growing states of its time despite its small size.
However, battles also took place in the 9th century on Curonian soil. The Swedes managed to defeat the Curonians in Grobina and Apuolė, extorting tribute from the locals. However, their long term presence was unsustainable and they had to abandon their settlements in Curonia. Numerous Viking graves and mounds have also been excavated in the area of Grobina, showing extensive contact between Balts and Norse.
Curonians might have also had closer ties to the Baltic Prussians, given their relatively close proximity as well as curious cases of Prussian surnames amongst Latvians (i.e Prūsis) and similarities with the Baltic Prussian language present in surviving Curonian records.
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