I’ve blogged this text before while looking at songs for a Corpus Christi Mass, but OCP set it to MELCOMBE by Samuel Webbe rather than DUGUIT. The words are by St Thomas Aquinas and are here translated by Edward Caswell, with editing by OCP.
O saving Victim, open wide
The gate of heaven to us below,
Our foes press on from every side,
Your aid supply, Your strength bestow.
To your great name be endless praise,
Immortal Godhead, One in Three;
O grant us endless length of days,
In our true native land with Thee. Amen.
Most version online are in Eb, as below, but OCP brings it down to C – thanks be to God.