Birger Jarl in the context of "Duchy"

Stockholm (/ˈstɒkhoʊ(l)m/; Swedish: [ˈstɔ̂kː(h)ɔlm] ) 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 2.5 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.

Stockholm is the cultural, media, political, and economic centre of Sweden. The Stockholm region alone accounts for over a third of the country's GDP, and is among the top 10 regions in Europe by GDP per capita. Considered a global city, it is the largest in Scandinavia and the main centre for corporate headquarters in the Nordic region. The city is home to some of Europe's top-ranking universities, such as the Karolinska Institute (medicine), KTH Royal Institute of Technology, Stockholm School of Economics and Stockholm University. It hosts the annual Nobel Prize ceremonies and banquet at the Stockholm Concert Hall and Stockholm City Hall. One of the city's most prized museums, the Vasa Museum, is the most visited museum in Scandinavia. The Stockholm metro, opened in 1950, is well known for the decor of its stations; it has been called the longest art gallery in the world. The city was the host of the 1912 Summer Olympics, and has played host to several other international sports events since.

The House of Sverker were a powerful political force in medieval Sweden, contesting for royal power. Their origins were in Östergötland. After the extinction of the House of Stenkil and the ascension of Sverker I of Sweden in 1130, a civil war commenced. In the beginning, there were several pretenders, of whom Sverker I emerged as victorious, for a time. The antagonists in the long run were finally the House of Sverker in Östergötland and the House of Eric in Västergötland and Uppland (Saint Eric was killed and buried in the latter province, others in the dynasty were buried in Varnhem Abbey in the former province as later also Birger Jarl was, a relative to the dynasty), which alternated on the throne for several generations, until in the 1220s the Eric dynasty got the upper hand, and the Sverker dynasty became extinct (at least in the male line).

As usual in medieval succession rivalries, the outcome combined the blood of rival lines, as in 1250 Valdemar of the Folkungs (then a minor, his father Birger Jarl acting as regent) ascended the throne, having inherited the Eric dynasty claim from Valdemar's mother (who was sister of Eric XI of Sweden, the last Eric-dynast) and some of the Sverker dynasty claim from Birger's mother (who was daughter of a younger son of Sverker I).

Ingeborg Eriksdotter (after 1214 – 17 June 1254) was a Swedish princess, daughter of King Erik Knutsson, eldest sibling of King Erik Eriksson, wife of Birger Jarl, and mother of Kings Valdemar and Magnus Ladulås.

The Second Swedish Crusade was a military expedition by the Kingdom of Sweden into Tavastia (Häme) in southern Finland described by Erik's Chronicle. According to the chronicle, the Swedes defeated the pagan Tavastians under the leadership of Birger Jarl, and started building a castle in Tavastia.

The expedition has traditionally been dated to 1249–1250 based on the chronology of the chronicle. However, some researchers have suggested that the expedition instead took place already in 1238–1239, shortly after the Tavastian uprising and before the Battle of the Neva against the Novgorod Republic. The castle that the Swedes began constructing during the expedition has traditionally been identified as Häme Castle, but it may also have been the older Hakoinen Castle.

Riddarholmen (Swedish: [ˈrɪ̂dːarˌhɔlːmɛn], "The Knights' Islet") is a small islet in central Stockholm, Sweden. The island forms part of Gamla Stan, the old town, and houses a number of private palaces dating back to the 17th century. The main landmark is the church Riddarholmskyrkan, used as Sweden's royal burial church from the 17th century to 1950, and where a number of earlier Swedish monarchs also lie buried.

The western end of the island gives a magnificent panoramic and photogenic view of the bay Riddarfjärden, often used by TV journalists with Stockholm City Hall in the background. A statue of Birger Jarl, traditionally considered the founder of Stockholm, stands on a pillar in front of the Bonde Palace, north of Riddarholm Church.

Birger Jarlsgatan is one of the longest streets in central Stockholm, Sweden. The street forms the border between Östermalm and the two neighbouring districts Norrmalm and Vasastaden.

It is named after Birger Jarl since 1885, then "Birger Jarls gata" (gata meaning "street"). The contemporary spelling has been used since 1932.