In 1625, 13 families lived on the island, making a living from farming, fishing and the production of "muschelkalk" or shell-bearing limestone. In later years, whaling and shipping became increasingly important to the island. During the Napoleonic occupation, shipping came to a halt due to the blockade against England which led to great poverty. Smuggling goods to and from the then English Heligoland was the only source of income during that time. In 1812, England attacked the French settlements on the island, but was repelled.