St. Bartholomew's Church is one of the oldest church buildings in Ljubljana. The church was first mentioned in 1370, when in front of it a peace treaty between the Doge of Venice and Leopold III and Albert III of Habsburg was concluded by their representatives on 30 October 1370, in which the Austrians agreed to return the city of Trieste for the compensation of 75,000 florins.
In 1526, its valuables were donated to a fund for improving the city's defenses against Turkish attacks. In the end of 15th century and beginning of 16th, it was a venue of Protestant liturgy and was during Slovene anti-reformation in 1618, it was reclaimed as a Roman Catholic church. In 1825, it was damaged by fire and restored several times.
Some elements of the original Romanesque church have been preserved, among them the portal on the northern side. Between 1933-36, the church was partially redesigned according to plans by Jože Plečnik.
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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.