Q: I’m looking over for an Anniversary Mass for a couple, and there is no indication given for what the Preface should be for an Anniversary Mass of Marriage. Since this is the case, am I right to assume that any Preface from the Ritual Mass for the Celebration of Marriage is permitted? If not, which Prefaces are permitted for an Anniversary Mass of Marriage?
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A: Since this is the anniversary and not the sacrament itself, you use the appropriate prayers for the occasion from the missal. See Order of Celebrating Matrimony 237 as a source.
Mass #11 in the Missal refers you to the Mass #49 for Giving Thanks to God, which recommends the Common Preface IV.