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.

Stockholm is the capital and most populous city of Sweden as well as the largest urban area in the Nordic countries. Approximately 1 million people live in the municipality, with 1.6 million in the urban area, and 2.4 million in the metropolitan area. The city stretches across fourteen islands where Lake Mälaren flows into the Baltic Sea. Outside the city to the east, and along the coast, is the island chain of the Stockholm archipelago. The area has been settled since the Stone Age, in the 6th millennium BC, and was founded as a city in 1252 by Swedish statesman Birger Jarl. The city serves as the county seat of Stockholm County.