French Romantic composer Gabriel Fauré (1845-1924) wrote at least three different choral versions of Tantum Ergo, a hymn that is usually sung during Holy Eucharist: 

[1] Op. 55 (1904), written for solo Soprano or Tenor with organ and harp accompaniment

[2] this version, Op. 62 No. 2, originally written in 1894 for SSA (three female voices), also with organ accompaniment

[3] the third version, without opus number, is for Soprano (or Tenor) solo with organ accompaniment and a unison final part (also harmonised for SATB in another edition)

This Fullscore Music arrangement for solo piano is faithful to the original choral setting except for the addition of held bass notes in the last three bars. In the original setting the first bar is an organ lead-in for the choir, who commence singing the tune in bar two. Pedalling should be freely used throughout, in order to achieve the legato, smooth choral feel; occasional suggestions are, however, included.

The original choral version uses the lyrics from the last two stanzas of the Eucharistic hymn, which is generally attributed to St Thomas Aquinas (c. 1264). It is used during veneration and benediction of the Blessed Sacrament in the Catholic Church. The hymn’s Latin incipit literally translates as ‘Therefore so great’.

Latin:

Tantum ergo Sacramentum

Veneremur cernui:

Et antiquum documentum

Novo cedat ritui:

Praestet fides supplementum

Sensuum defectui.

Genitori, Genitoque

Laus et Jubilatio,

Salus, honor, virtus quoque

Sit et benedictio:

Procedenti ab utroque

Compar sit laudatio. Amen.

Translation:

Down in adoration falling,

Lo! the Sacred Host we hail,

Lo! oe'r ancient forms departing

Newer rites of grace prevail;

Faith for all defects supplying,

Where the feeble senses fail.

To the Everlasting Father,

And the Son Who reigns on high

With the Holy Ghost proceeding

Forth from Each eternally,

Be salvation, honour blessing,

Might, and endless majesty. Amen.

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Recording of the original choral piece, sung by the Cambridge Singers (cond. John Rutter with John Scott, organ), 2m 33s: https://youtu.be/9yiksQ-1uhk 

Follow-along animated score of SSA choral version: https://www.youtube.com/watch?v=oQxn95AEW-4