 Christianity may have been introduced in the 3rd century by Felix and Regula, with whom Exuperantius was associated – according to the Christian legend, Felix and Regula and their servant were executed at the location of the Wasserkirche in 286.Using the advantage of topography, the Roman military built a citadel on top of the Lindenhof hill in the years of the Roman emperor Valentinian I (364–375), to defend migrations from the North by the Alamanni.4500 m2 large, it was fitted with 10 towers and two meter wide walls.