O Salutaris Hostia is from the last two verses of Verbum Supernum. one of the five Eucharistic Hymns written by St. Thomas Aquinas; (1225-1274) at the request of Pope Urban IV (1261-1264) when the Pope first instituted the Feast of Corpus Christi in 1264. The prayer is still used today, often at exposition of the Blessed Sacrament.

O salutaris Hostia

Quae coeli pandis ostium.

Bella premunt hostilia;

Da robur, fer auxilium.

Uni trinoque Domino

Sit sempiterna gloria:

Qui vitam sine termino,

Nobis donet in patria.

Amen.

O Saving Victim opening wide

The gate of heaven to all below.

Our foes press on from every side;

Thine aid supply, Thy strength bestow.

To Thy great name be endless praise

Immortal Godhead, One in Three;

Oh, grant us endless length of days,

In our true native land with Thee.

Amen.