Nyköping Castle

[1][2] Construction on the castle is thought to have begun at the end of the 12th century, when it was built as a sort of castellum.

During the reign of Albert of Sweden the castle was held as a fief by the German knight Raven van Barnekow, who made important improvements on the building, and later by Bo Jonsson Grip.

Gustav Vasa strengthened the castle further for defensive purposes and a round gun tower from that time remains today.

Erik Sparre – taken prisoner after Charles defeated Sigismund III Vasa's forces at the Battle of Stångebro – was held in the castle until his execution at the Linköping Bloodbath.

It wasn't reerected; in fact some of its bricks were used in the construction of Stockholm Palace.