It is an interesting study to look back into the hymnology of the early church. According to the various sources (most catholic, I admit) This one, translated from Greek dates back to around 150 AD, and there is some evidence that it may have been sung them in the catacombs. Below are two translations of this early hymn called "Phos Hilaron"
O Gracious Light
pure brightness of the everlasting Father in heaven.
O Jesus Christ, holy and blessed!
Now as we come to the setting of the sun,
and our eyes behold the vesper light,
we sing praises, O God:
Father Son and Holy Spirit.
You are worthy at all times
to be praised by happy voices,
O Son of God, O Giver of life,
and to be glorified through all the worlds.
- Book of Common Prayer
[Oxford University Press, New York. Permission requested.]
O gladsome Light, O Grace
Of God the Father's Face,
The eternal splendor wearing;
Celestial, holy, blest,
Our Savior Jesus Christ,
Joyful in Thine appearing.
Now, ere day fadeth quite,
We see the evening light,
Our wonted hymn outpouring,
Father of might unknown,
Thee, His incarnate Son,
And Holy Ghost adoring.
To Thee of right belongs
All praise of holy songs,
O Son of God, Life-giver;
Thee, therefore, O Most High,
The world doth glorify
And shall exalt forever.
- Robert Bridges, 1899
Another source for early hymns is found at this site
Hymns of the Early Church | Christian Classics Ethereal Library
What I find interesting is that as early as 300 AD church leaders were arguing about the use of hymns vs. psalms only. So folks, we are not new to this debate!