This paper examines the Sermons of Leo the Great (a.d. 440–461) for their liturgical topography. Leo developed an annual cycle of set places on set days — the very definition of stational liturgy — in Rome as one means to assert papal authority over the city's Christian communities and especially over the resident Roman senatorial aristocracy. Leo's Sermons indicate that the bishop found new ways to centralize the liturgy at St Peter's in the Vatican, making St Peter's — not St John the Lateran — the religious centre and the symbol of the papacy.