Nordic history refers to the historical development of the countries in Northern Europe, primarily Denmark, Norway, Sweden, Finland, and Iceland. This region has a rich past that includes the Viking Age, when seafaring Norse explorers and traders expanded their influence across Europe and beyond from the 8th to the 11th centuries. The Vikings are known for their raids, settlements, and cultural exchanges. In the Middle Ages, the Nordic countries experienced significant political changes, including the formation of unions, such as the Kalmar Union in 1397, which united Denmark, Norway, and Sweden. The region later underwent the Protestant Reformation and faced various conflicts, including the Great Northern War in the early 18th century. Today, the Nordic countries are known for their strong welfare systems and high quality of life.