Sweden has a population of approximately 9.5 million people and its capital and largest city is Stockholm. In the 8th-10th centuries, Swedish Vikings traveled east across the Baltic Sea, settling in Finland and trading with Baltic countries. Gustav Vasa established Protestantism in Sweden and strengthened the state in the 16th century. Through successful wars, Sweden became an empire but lost its empire status after defeat in the Great Northern War in the early 18th century. Sweden industrialized in the 19th century and established a democratic welfare state in the 20th century.