Prehistory and Origin of Stockholm - Origin

Origin

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 Sturluson 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.

While the reliability of these stories remains disputed, dendrochronological examinations of logs driven into the seabed in Norrström, square oak logs, and sunken logs found on Helgeandsholmen just north of Stadsholmen in 1978-1980, concluded these trees were cut down during the period 970-1020, most of them from around 1010, and these logs presumably gave the entire city its present name, Stock-holm, "Log-Islet".

Anyhow, any hypothesis on the origin of the city necessarily need to depart from three poorly documented defensive structures:

1. Some kind of original primitive redoubt surrounded by wooden barriers probably constructed during the Viking era (i.e. around 1000).
2. A bailey and a larger building located on a pair of islets now part of Helgeandsholmen accompanied by a row of poles forming a barrier in the strait (i.e. the "lock" of Lake Mälaren).
3. A castle built on the north-eastern corner of Stadsholmen, a construction probably initiated by Birger Jarl in the mid 13th century and completed around 1300. It is possible the construction of this castle started simultaneously with the second defensive structure mentioned above and that this structure became outdated as the castle was completed.

It is often said the tower of the Three Crown Castle originated from at least parts of these defensive structures. As historical and archaeological records are fragmentary, the origin of this tower and the castle remain open for various interpretations, as do the size and extent of the city at the time. Some researchers conclude Stockholm evolved into the Swedish capital and an important trade city before 1200 (Kumlien), while others suggest the location remained a mostly rural area around 1250 to quickly expand into large city before the castle was completed (Hansson, Ödman).