Kingdom of Sweden

Swedish pre-history ends around 800 AD, when the Viking Age begins and written sources are available. During the following centuries, Sweden gradually consolidated as a single nation. The Viking Age lasted until the mid-11th century. Scandinavia was formally Christianized by 1100 AD. The period 1050 to 1350—when the Black Death struck Europe—is considered the Older Middle Ages. The period from 1350 to 1523 is considered the Younger Middle Ages. The Kalmar Union between the Scandinavian countries was established in 1397 and lasted until King Gustav Vasa ended it upon seizing power during the Swedish War of Liberation, which concluded in 1523.