Almarestäkets castle was built in the 1100s to protect the Sigtuna and Uppsala cities. It was also called as St. Erik's castle after Eric IX. Throughout the Middle Ages there was a struggle between the Crown and Church who can control the castle.
The castle was first mentioned in the late 1300s. In 1440 got Archbishop Nicolaus Ragvaldi permission to build a new castle, which was completed about ten years later. In the 1510s troubles Almarestäkets was in possession of Bishop Gustav Trolle between 1516-17. The castle was sieged by his main enemy Sten Sture the Younger in 1517. Archbishop Gustav Trolle locked himself in there to avoid trial, and the Swedish government demanded and carried out the demolition of the fortress. The procedure was formally unauthorized because at the time State property was to be separate from Church property. As a revenge for this and other perceived injustices, Trolle, assisted by the Danish King Christian II, took revenge in the Stockholm Bloodbath of 1520.
Today there are visible traces of castle foundations with potholes filled with stone and occasional bricks.
References:The Château du Lude is one of the many great châteaux of the Loire Valley in France. Le Lude is the most northerly château of the Loire Valley and one of the last important historic castles in France, still inhabited by the same family for the last 260 years. The château is testimony to four centuries of French architecture, as a stronghold transformed into an elegant house during the Renaissance and the 18th century. The monument is located in the valley of Le Loir. Its gardens have evolved throughout the centuries.