This spring belongs to the Petrinium. The source used to donate the water for the school and boarding school for several decades now. Over the years, the natural grotto has developed into an unofficial place of worship. Whether it is actually the legendary "origin" of the pilgrimage to the Pöstlingberg has not been proven. Although modified by the Maximilian fortifications, the Pöstlingberg was definitely a pre-Christian place of worship because of its dominant position and the similarity to other cult mountains in the area. Näpfchensteine and a bowl stone were found at the edge of the Mayrwiese. ... Near the 5th Station of the Cross on the Pöstlingberg "a rock structure, in whose cracks and crevices all kinds of plants grow rampant. At the foot of the wall there is a natural shallow pool with fresh, clear spring water. It has physically and chemically good, very soft water. People call the water the sacred Bründl. It has a reputation for healing sick eyes. Many people go to this water source, moisten and wash their eyes. ..." as far as an article from the Volksblatt, year 1952, where Franz Harrer's pilgrimage to the Pöstlingberg is quoted.