Estuna Church dates from the early 13th century or possibly the late 12th century. The structure of the building indicates that a tower was initially planned for the eastern end of the church but never built. It may have been intended as a defensive tower which became redundant as times became more peaceful as the Middle Ages progressed in Sweden.
The church has been rebuilt and expanded several times. During a renovation of the altar in 1733 a patch of parchment was discovered that noted the date of a re-inauguration of the church to 1298. This was probably done in connection with an enlargement of the church towards the west. The church porch was added during the 15th century. During a renovation in the 20th century, medieval frescoes were discovered and uncovered. Among the church furnishings, most date from the 18th century. The baptismal font is however older, from the 13th century. The elaborate crucifix was donated to the church in 1783 and made in Rome.
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.