O Arglwydd Dduw sancteiddiol Dad

O Arglwydd Dduw, sancteiddiol Dad,
O Iesu Grist yr Un Mab rhad,
  O Yspryd nef,
      Ddyddanydd Glân,
  Un Duw tragwyddol di-wahân.

Drindod yn Undod mawr dy nerth,
Gwir Dduwdod o anfeidrol werth,
  Llewyrch angylion -
      noddfa glyd
  I'r gwan - a'n gobaith
      oll i gyd.

Ar bob rhyw beth mae genyt hawl,
Y greadigaeth gân
    Dy fawl;
  Ninau ddadseiniwn lafar lef, -
  O! erglyw ni o gaerau'r nef.

A rhoddwn it' ogoniant gwiw,
Hardd Dri yn Un, oruchel Dduw;
  Emyn, a mawl,
      a pharch dilyth,
  A weddant iti, Arglwydd, byth.

O Lord God, sacred Father,
O Jesus Christ the One gracious Son,
  O Spirit of heaven,
      Holy Comforter,
  One eternal, undivided God.

Trinity in Unity with thy great strength,
True Godhead of immeasurable worth,
  The brightness of angels -
      a secure refuge
  For the weak - and all
      our hope altogether.

Over every kind of thing thou hast right,
The creation song
    thy praise;
  We too resound a loud cry, -
  O hear us from the fortresses of heaven!

And we give to thee worthy glory,
Beautiful Three in One, most high God;
  Hymn, and praise,
      and sincere reverence,
  Befit thee, Lord, forever.

O Holy Father, gracious Thou and tender;
  O Jesus Christ, Thou much adorčd Son;
Spirit most sweet,
    Thou Paraclete, Defender,
  Eternally one!

Trinity Holy, Unity abiding,
  True God Thou art,
      unbounded goodness Thou,
Light of the angels,
    trust of the confiding,
  We hope in Thee now.

Thee all creation pays eternal homage;
  Thee all Thy creatures
      songs of glory raise;
Now come we humbly, joining in the chorus,
  O hear Thou our praise.

Glory to Thee, O God of power almighty,
  Triune yet One, and great Thou art and high;
Hymns fitly tell Thy honour,
    praise, and glory,
  And eternally.

from the Latin
O Pater sancte mitis atque pie
10th Century