St. Thomas Aquinas: Tantum Ergo Sacramentum

English translation
A translation over a hundred years old and still used in Catholic churches liturgically renders the hymn thus, in a form which can be sung to the same music as the Latin:

Down in adoration falling,
Lo! the sacred Host we hail,
Lo! o'er 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, honor, blessing,
Might and endless majesty.
Amen.
V. Thou hast given them bread from heaven.
R. Having within it all sweetness.

V. Let us pray: O God, who in this wonderful Sacrament left us a memorial of Thy Passion: grant, we implore Thee, that we may so venerate the sacred mysteries of Thy Body and Blood, as always to be conscious of the fruit of Thy Redemption. Thou who livest and reignest forever and ever.

R. Amen.

(Translation from here.)