History of the North Sea great herring fishing industry resulting in Scotland becoming a European leader in that industry. During the First Schleswig War (1848–51), the Crimean War (1854–56) and the Second Schleswig War (1864), belligerents took steps to reduce or eliminate commerce in the North Sea by their enemies. In the first Schleswig War, Denmark was able to halt maritime commerce by Germany in the North Sea and in the second, imposed tolls on ships crossing through the Danish straits between the Baltic and North Seas. The Crimean War saw British and French expeditions sent into the Baltic to prevent Russian ships' egress into
History of the North Sea Danelaw, carving out his own kingdom. Harthacanute of Denmark and England was the last Viking king to rule over a territory spanning the North Sea. After Harthacanute's death, the kingdom broke apart. With the rise of William the Conqueror the North Sea began to lose its significance as an invasion route. The new order oriented most of England and Scandinavia's trade south, toward the Mediterranean and the Orient. The Baltic Sea became increasingly important for northern Germany and Scandinavia as well as the powerful Hanseatic League began to rise. Though the Hanseatic League was centered in the Baltic, it also