Birger Jarl, also known as Birger Magnusson, was a Swedish statesman and regent, jarl, and a member of the House of Bjelbo, who played a pivotal role in the consolidation of Sweden. His first marriage was to Princess Ingeborg of Sweden, which created his base of power. Birger led the Second Swedish Crusade, which established Swedish rule in Finland. Additionally, he is traditionally attributed with the foundation of the Swedish capital, Stockholm, around 1250. Birger used the Latin title of Dux Sweorum, and the design of his coronet combined those used by continental European and English dukes.

Swedish pre-history ends around 800 AD, when the Viking Age begins and written sources are available. 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 Kalmar Union between the Scandinavian countries was established in 1397 and lasted until King Gustav Vasa ended it upon seizing power. The period 1350 to 1523 – when king Gustav Vasa, who led the unification of Sweden in the Swedish War of Liberation, was crowned – is considered the Younger Middle Ages. During these centuries, Sweden gradually consolidated as a single nation.