Tantum ergo

"Tantum ergo" is the incipit of the last two verses of Pange lingua, a Medieval Latin hymn composed by St Thomas Aquinas circa A.D. 1264.

The "Genitori genitoque" and "Procedenti ab utroque" portions are adapted from Adam of Saint Victor's sequence for Pentecost.

The singing of the Tantum ergo occurs during adoration and benediction of the Blessed Sacrament in the Catholic Church and other denominations that have this devotion.

[10] The basic text has been set by numerous composers: from the Classical period John Francis Wade,[11] the Renaissance (Palestrina), the Romantic period (Anton Bruckner, Hector Berlioz (H142), Gabriel Fauré, Franz Schubert, Louis Vierne), and modern composers (Maurice Duruflé, David Conte, Crys Armbrust).

The hymn, whose lyrics paraphrase the first two forms of the Memorial Acclamation of the Mass, is sung during the Wednesday Novena Service to Our Lady of Perpetual Help and Benediction at Baclaran Church (the icon's principal shrine in the country).