In the early modern period, the configuration of Sweden's borders made Gothenburg strategically critical as the only Swedish gateway to Skagerrak, the North Sea and Atlantic, situated on the west coast in a very narrow strip of Swedish territory between Danish Halland in the south and Norwegian Bohuslän in the north. After several failed attempts, Gothenburg was successfully founded in 1621 by King Gustavus Adolphus (Gustaf II Adolf).