Tanstein Castle is one of the three castles at Dahn; the others being Altdahn and Grafendahn. Although the three castles are sited next to one another on a hill ridge, they were not built at the same time.
Tanstein is the oldest of the three castles in the group. An 1127 document refers to an Anshelmus de Tannicka as the owner or governor; as a result the castle was probably built in the early 12th century. In 1189, in a deed by Emperor Frederick Barbarossa, a Henry von der Than is mentioned and the castle designated as an immediate imperial fief. In the period that followed, Ulrich of Dahn and Conrad of Dahn are named as imperial ministeriales. In 1328 the castle became a fief of the bishops of Speyer. Until 1464 there were frequent changes of ownership, which suggests that the fief was still not inheritable during this phase, but was always re-enfeoffed.
In 1512 Frederick of Dahn purchased the castle. Because he was an ally of the knight, Franz von Sickingen, he was involved in his battles against the imperial princes in southwest Germany. After Sickingen's defeat and death in 1523, Tanstein, too, fell into the hands of the victors. Its occupation by troops of the Archbishop of Trier lasted until 1544 and probably led to irreparable damage to the structure of the castle, because it was finally abandoned in 1585. In 1689, at the start of the War of the Palatine Succession, the French completely destroyed the ruins.
Tanstein Castle is located on the two westernmost rock outcrops of the Dahn castle cluster. Both were originally linked by a bridge. On the rocks today are modern parapet walls that have been rather arbitrarily added and do not give any real idea of the old castle buildings. On the western rock outcrop there were apparently domestic-like buildings, that were built against the rocks. This is evinced by putlock holes and other marks on the rocks as well as a large cistern, in which water from the roofs was gathered and stored.
The lower ward on the southern rock outcrop still shows traces of the original walls dating to the 15th century. These include the ruins of a smithy and a smelting furnace.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.