In the 15th century the construction of the city walls continued both to the west towards Lake Mälaren and in the east towards Saltsjön until the 16th century. Moreover, barricades were adapted all the time to the prevailing political and military-technical conditions. Therefore, the wall reinforcement was concentrated in the direction in which attacks on Stockholm were likely to come. This means that the wall to the east and Saltsjön strengthened during periods in which a Danish invasion by sea was feared,For example, during Sten Sture the Elder time in 1400 century while reinforcements of Mälarmuren was carried out during the first part of Gustav Vasa's reign (c. 1530-1540), when attacks from domestic insurgents via Mälaren was feared to come.
