It was first mentioned in Russian chronicles as Beryozovskoye (, lit. birch village) in 1268, when the Hanseatic merchants from Gotland petitioned the Novgorod Republic to secure their passage to the Neva River. The original Finnish name Koivisto means "a group of birch trees", "a birch forest". Swedish name Björkö means "birch island". Swedes annexed the region during the Third Swedish Crusade. The Russians retook the islands at the close of the Great Northern War in 1721. This was confirmed by the Treaty of Nystad in 1721.