Kluskirche in Giershagen

In the 12th century, the Klus Church in Niederuppsprunge was built on the site of a Carolingian-era chapel. It was originally a single-nave Romanesque structure with a square tower designed as a windowless defensive tower. The original Romanesque structure was expanded in 1682 by Abbot Absalom Heuck of Bredelar to include a square bay and a chancel extension to the east. This addition, with its ribbed cross vaults, stands out distinctly from the older section.
In 1700, the church received a new Baroque altar, which, like many wayside shrines in the Giershagen area, originated from the Papen workshop. The sculpture workshop of Heinrich Papen (1645–1719) and his son Christophel (1678–1735) in Giershagen was one of the leading and most prolific workshops of the Baroque period in Westfalen. It worked with alabaster, marble, and Mehlstein, the types of stone found in the surrounding area. They left behind an extensive body of work comprising over 160 works of art, including more than 40 altars, in more than 50 locations throughout Westfalen and the North Hessian-Waldeck region. Early on, the Klus Church, dedicated to Saints Fabian and Sebastian as its patron saints, became a place of pilgrimage where miraculous healings were said to have occurred. This was evidenced in the past by the many items pilgrims had left behind in the church.
Once a year, a solemn procession to the Klus Church took place with large participation from the neighborhood, followed by a church fair (Kirmes).
In 1475, a papal indulgence was granted for participation in this pilgrimage. In 1693, Pope Innocent XII renewed the plenary indulgence for visiting the Klus Church on major feast days and during processions.

Due to its art-historical significance, the church was preserved in the years that followed and underwent several major restorations (e.g., by the RAD in the 1930s, and most recently at a cost of €700,000 by the State of North Rhine-Westphalia). The state of North Rhine-Westphalia is responsible for its upkeep because the church is one of the few patronage properties owned by the state. Patronage properties are buildings owned by the state for which the state is responsible for maintenance. In the course of secularization (the Imperial Deputation Main Resolution of 1803), the state undertook to assume responsibility for the maintenance of patronage buildings as compensation for expropriated church property. These maintenance obligations were transferred to the State of North Rhine-Westphalia upon its founding in 1946, as the legal successor to the State of Prussia.