The Kaufmannskirche St. Gregor (Merchant's Church St Gregory) is a 14th-century Gothic parish church at Anger Square. It is one of the largest and most important original parish churches in Erfurt. The parents of Johann Sebastian Bach, Johann Ambrosius Bach and Maria Elisabeth Lämmerhirt married here in 1668.
The former Romanesque building (11th century) on the site was burnt down in 1291. The consecration of the Gothic basilica with twin choir towers took place in 1368. The altar (1625), pulpit (1598), baptismal font (1608), epitaphs (1584/85/90) are works of the Thuringian Late Renaissance and forms of Luther iconography of Erfurt sculptors and stone masons Hans Friedemann, the Elder and Younger. Martin Luther preached here on 22th October 1522.
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.