St. James's Parish Church was built in the Baroque style between 1613 and 1615 on the site of an older Gothic style church, erected in the early 15th century by the Augustinian Order. In 1598, the old church was acquired by the Jesuits and thus became the first Jesuit church in the Slovene Lands and one of the first in the Inner Austria. The interior was designed by the Italian architect Francesco Robba, who designed the main altar, and the Slovene stonemason Luka Mislej, who designed the entrance portal and the stone side altars. After the Ljubljana earthquake of 1895, the church was renovated by the Linz-based architect Raimund Jeblinger and the interiors were redesigned by Janez Šubic. Nevertheless, much of the original Baroque style has remained intact.
On the side of the church there is a column erected in 1682 to commemorate the Habsburg victory against the Ottoman Turks in the Battle of Saint Gotthard. The column, dedicated to the Virgin Mary, was designed by the Salzburg-based artist Wolf Weisskirchner upon the plan by Johann Weikhard von Valvasor.
In the late 1920s, the square in front of the church was renovated by the Slovene architect Jože Plečnik, and in the early 1950s by the architect Boris Kobe. Opposite St. James's Church is the Gruber Palace, which houses the Slovenian National Archives.
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.