The Palace of the Grand Dukes of Lithuania was built originally in the 15th century for the rulers of the Grand Duchy of Lithuania. The Royal Palace in the Lower Castle evolved over the years and prospered during the 16th and mid-17th centuries. For four centuries the palace was the political, administrative and cultural center of the Grand Duchy of Lithuania.
Soon after the Grand Duchy of Lithuania was incorporated into Tsarist Russia, Tsarist officials ordered the demolition of the remaining sections of the Royal Palace. The Palace was almost completely demolished in 1801, the bricks and stones were sold, and the site was bowered. Only a small portion of the walls up to the second floor survived, that were sold to a Jewish merchant Abraham Schlossberg around 1800 who incorporated them into his residential house. After the 1831 uprising, the czarist government expelled Schlossberg and took over the building as it was building a fortress beside it. Before the Second World War it was the office of the Lithuanian Army, during the World War II it was the office of the German Army, and after World War II it was used by Soviet security structures and later transformed into the Palace of Pioneers. Fragments of Schlossberg's house have become part of the Eastern Wing of the restored Royal Palace.
A new palace has been under construction since 2002 on the site of the original building. The Royal Palace was officially opened during the celebration of the millennium of the name of Lithuania in 2009.References:
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.