In earlier times, the nearby river Acher often burst its banks. The masses of water tore away bridges and footbridges, damaged the mostly lightly built houses and flooded fields and meadows for miles around. It was therefore natural for the believing people to look for a patron saint to protect them from the dangers of water: St Nicholas, Bishop of Myra, the legendary helper in water emergencies, was to provide relief. As one of the most celebrated folk heroes of the West, every child knows St Nicholas, who knocks on the door at the beginning of the Christmas season.
According to local tradition, the entrails of the French Marshal Turenne were buried in the Klauskirchl in 1675. Turenne was killed in the Battle of Sasbach against the Imperial General Montecuccoli. However, they were not found in the chapel during investigations by the French government in the 19th century. Excavations during the installation of a heating system in 1973 were also unsuccessful.
According to legend, the inhabitants of Reeß, the district of Achern adjacent to St Nicholas' Chapel, dug up the copper cauldron with the entrails soon after the burial.