This study, based on twelfth-to-fourteenth-century inscriptions in the west of France, tries to understand the links between formula and epigraphy, formula and language, and formula and source.1) The 'hic jacet' formula is an epigraphic and funerary Latin phrase which indicates a place of burial. Its popularity increases during the 12th, 13th, 14th centuries, linked to the rise of incised slabs. Always in initial position in the text, this formula introduces the rest of the epigraph. On effigial tombs, its location is strategic, above the dead's head. Its rise is also linked to the advent of prose. 2) Can a formula transleted in vernacular language still be recognized as a formula? The examples of 'hic jacet and anima requiescat in pace' illustrate two possibilities. The French translation of 'hic jacet, ci-gît', is very close to the Latin phrase. On the other hand, there are several translations of anima requiescat in pace, in French: 'faire pardon' and 'faire merci' are the most common. focused on mercy, they don't have the same meaning as the Latin formula and are rather an adaptation to the French language and the theological thought time. 3) 'Anima requiescat' is both inspired by the Bible (Psalm 4, 9) and the liturgy (the funeral mass) in Latin. That is why this formula is translated with difficulty. The vernacular language creates its own idiomatic expression. The author of inscriptions can also draw his inspirations from "sylloges", literary writings, oral tradition or readings of tombs. A lecary from ancient Christian epigraphy, 'hic jacet' may use all these meanings. The use of formulae in epigraphy is also an anesthetic choice. They give structure to the text. The reader expects them and recognizes them, like textual "beacons".