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.
History of Stockholm
Following the Thirty Years' War (1618–1648), Sweden was determined never to repeat the embarrassment experienced following the death of Gustavus II Adolphus (1594–1632) when Stockholm, still medieval in character, caused hesitation on whether to invite foreign statesmen for fear the lamentable appearance might undermine the nation's authority. Therefore, Stockholm saw many ambitious city plans during the era, of which those for the ridges surrounding today's old town still stands. In accordance to the mercantilism of the era, trade and industry was concentrated to cities where it was easier to control, and Stockholm was of central importance. In a letter in 1636, Chancellor Axel Oxenstierna (1583–1654) wrote that evolving the Swedish capital was a prerequisite for the nation's power and strength and that this would bring all the other cities on their feet. Increased state intervention on city level was not unique to Sweden at this time, but it was probably more prominent in the case of Stockholm than anywhere else in Europe. To this end, the government of the city was reformed and the former volunteered magistrates gradually replaced by professionals with a theoretical education.