Prehistory and origin of Stockholm
According to the Chronicle of Eric, written in the 1320s, Stockholm was founded by Birger Jarl around 1250 as a lock to the Lake Mälaren region ("laas fore then sio", "lock before that lake") in order to prevent pirates from reaching the seven cities and nineteen parishes around it. Another medieval source ("Visbyannalerna"), however, claims the city was founded in 1187 following a pagan pillaged the city of Sigtuna, and as there was an "Earl" named Birger around at that time too, the disputed origin of the city are likely to remain obscure and some historians choose a diplomatic interpretation saying there was some sort of fortification around by the mouth of lake Mälaren when the city was founded during the second half of the 13th century. As Snorri mentions no city in his account but some sort of fortification called a "kastali" (in various manuscripts curiously said to be located east and west of "Stocksund"), it has generally been assumed this fortification eventually developed into the castle Tre Kronor located where still is the Stockholm Palace.
Stockholm
Stockholm is Sweden's financial centre. Major Swedish banks, such as Swedbank, Handelsbanken, and SEB, are headquartered in Stockholm, as are the major insurance companies Skandia, Folksam and Trygg-Hansa. Stockholm is also home to Sweden's foremost stock exchange, the Stockholm Stock Exchange ("Stockholmsbörsen"). Additionally, about 45% of Swedish companies with more than 200 employees are headquartered in Stockholm. Noted clothes retailer H&M is also headquartered in the city. In recent years, tourism has played an important part in the city's economy. Stockholm County is ranked as the 10th largest visitor destination in Europe, with over 10 million commercial overnight stays per year. Among 44 European cities Stockholm had the 6th highest growth in number of nights spent in the period 2004–2008.