St Peter's Abbey in the Black Forest (Schwarzwald) is a former Benedictine monastery. The monastic community was the house monastery and burial place of the Zähringen family. It was originally founded in Weilheim, in or before 1073, but was forced by hostile military action during the Investiture Controversy to move to Hirsau. Duke Berthold II of Zähringen (1078–1111) re-founded it as a family monastery, but decided in about 1090 to move it to the site which is now St. Peter im Schwarzwald.
Here it soon developed as a reformed Benedictine monastery directly answerable to the papacy, as witness for example the privilege of Pope Urban II of 10 March 1095. The Vögte (lords protectors) were initially the Zähringen family but, in the late 13th century, they were succeeded by the Counts of Urach, against whom the monks were eventually obliged to seek the protection of Emperor Charles IV. In 1526 the office passed to the Habsburgs.
By the gift of the Zähringen family and their ministeriales the abbey acquired substantial property, particularly in the 11th and 12th centuries, located in the immediate area, in the Breisgau and in the Baar region, near Weilheim. The abbey, like most other landowners of the time, suffered significant loss of income and tenants after the middle of the 14th century.
The abbey suffered disastrous fires in 1238 and again in 1437. It lost importance in the later mediaeval period, and the monastic reforms of the 15th century had little effect here. Nevertheless, it managed to keep its property intact, even through the troubles of the Reformation. The premises were re-built in Baroque style in the 17th and 18th centuries; the present church with the two onion towers was built in the 1720s. The architect was Peter Thumb, and the opulent Baroque decoration was by Franz Joseph Spiegler (55 frescoes, 1727) and Joseph Anton Feuchtmayer (sculptures), among other artists and craftsmen. Peter Thumb also constructed the library. The abbey was dissolved in the secularisation of 1806.
References:The Chapel of St. Martin is the only completely preserved Romanesque building in Vyšehrad and one of the oldest in Prague. In was built around 1100 in the eastern part of the fortified outer ward. Between 1100 and 1300, the Rotrunda was surrounded by a cemetery. The building survived the Hussite Wars and was used as the municipal prison of the Town of the Vyšehrad Hill.
During the Thirty Years’ War, it was used as gunpowder storage, from 1700 to 1750, it was renovated and reconsecrated. In 1784, the chapel was closed passed to the military management which kept using it as a warehouseand a cannon-amunition manufacturing facility. In 1841, it was meant to be demolished to give way to the construction of a new road through Vyšehrad. Eventually, only the original western entrance was walled up and replaced with a new one in the sountren side. The dilapidating Rotunda subsequently served as a shelter for the poor.