“Tantum Ergo” is a Medieval Latin hymn composed by St Thomas Aquinas circa A.D. 1264. The hymn’s Latin title literally translates to “Therefore so great”. Tantum Ergo is normally sung at Adoration / Benediction of the Blessed Sacrament.
Tantum ergo sacramentum
Veneremur cernui,
et antiquum documentum
novo cedat ritui.
Præstet fides supplementum
sensuum defectui.
Genitori genitoque
laus et jubilatio,
Salus, honor, virtus quoque
sit et benedictio!
Procedenti ab utroque
compar sit laudatio!
Amen.
Therefore, so great a SacramentLet us venerate with heads bowed [cernui] And let the old practice [documentum] Give way to the new rite; Let faith provide a supplementFor the failure of the senses.To the Begetter and the Begotten [both masculine gender],Be praise and jubilation,Hail, honour, virtue also,And blessing too: To the One proceeding from BothLet there be equal praise. Amen.