Axel Oxenstierna palace in the Old Town of Stockholm was designed by architect Jean de la Vallée to Chancellor Axel Oxenstierna and the construction started in 1653. The palace became the headquarters for the 1668-1680 Swedish Central Bank and after a series of state institutional policy.
The palace is uniquely conserved in particular to the exterior. There are state historic building since 1935 and is one of the Swedish architectural art's most significant and well-preserved works.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.