The chapel was consecrated to St Isidor and to the Ascension of the Virgin Mary.
Riegerting first appeared in historical documents as "Rueckering" in 1363. An extension of the chapel was recorded in 1685.
The Baroque-style high altar was designed by the renowned Ried sculptor Thomas Schwanthaler. In the 18th century a luxuriously decorated Rococo-style glass shrine containing the relics of St Dionysius the Martyr was fitted into the altar.
Up to the year 1821 admission to the chapel was exclusively granted to the owners of the castle. When Baron Philipp von Venningen purchased the castle in 1829, he opened the chapel to the public. Unfortunately, the chapel was seriously damaged by ground water in 1932 and has not been in use ever since. A new aisled church was erected in the place of the former tithe barn.