117 TU TRINITATIS UNITAS
A cento. Added to the Roman Breviary in 1568. In a subsequent edition it is the hymn for Lauds on Trinity Sunday. It is made up of the first stanza of a hymn with the same opening, and of the third stanza of the composition, Æterna cœli gloria, with a doxology added.
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III
| O Thou Eternal One in Three, Dread Ruler of the earth and sky, Accept the praise we yield to Thee, Who, waking, lift our songs on high. | | The star that tells the approach of day Is lingering in the glow of morn, And night and darkness fade away— O Holy Light, our souls adorn! | | To God the Father throned in heaven, To Christ the One Begotten Son, And to the Spirit praise be given, Now, and while endless ages run. | |