Source: PL-Wn 12722 V Graduał opata tynieckiego MścisławaFolio: 224rSequence: 1Feast: Cathedra PetriOffice: MASSGenre: TrVPosition: 01Cantus ID: g00030aMode: 2Full text: Et portae inferi non praevalebunt adversus eam et tibi dabo claves regni caelorumExternal image link: Image link