For more than a millenium, singers in churches, monasteries, and private chapels across Europe have closed their worship with the joyful musical exclamation Benedicamus Domino ('Let us Bless the Lord'). This moment has sounded in song many times a day: at the end of the Mass, the Office hours, outside the church walls in celebratory processions, as well as in informal sacred, devotional, and festive contexts. Benedicamus Domino was uniquely associated with an unprecedented amount of creative freedom in the sacred rituals of the Christian West: plainchant melodies could be adopted at will from other parts of the liturgy, and this moment inspired a proliferation of poetic and polyphonic elaborations from the eleventh century on. This collection of essays brings together interdisciplinary contributions from eighteen scholars, illuminating the wide range of ritual, musical, poetic, manuscript, and generic contexts for the Benedicamus Domino versicle in the period c.800-1650. Individual chapters engage with the evidence of liturgical commentaries and Patristic texts, Ordines, and hagiographies. They present and analyse musical and textual embellishments of the Benedicamus Domino, as well as their written traces and material contexts, with several sources discovered or discussed in detail here for the first time. Encompassing a wide geographical and generic scope, this volume reveals unsuspected continuities and contrasts in the history of the Benedicamus Domino versicle in medieval and early modern Europe.