Caedmon's Hymn

Now let us praise Heaven-Kingdom's Guardian,
the Maker's might and His mind's thoughts,
the work of the glory-Father—of every wonder,
eternal Lord. He established a beginning.
He first shaped for men's sons
Heaven as a roof, the holy Creator;
then middle-earth mankind's Guardian,
eternal Lord, afterwards prepared
the earth for men, the Lord almighty.

Nu scilun herga hefenricæs uard
metudæs mehti and his modgithanc
uerc uuldurfadur sue he uundra gihuæs
eci dryctin or astelidæ.
he ærist scop ældu barnum
hefen to hrofæ halig sceppend
tha middingard moncynnæs uard
eci dryctin æfter tiadæ
firum foldu frea allmehtig

(source)

This hymn was composed by Caedman, a monk or cow-herder working at the monastery of Streonæshalch in Yorkshire some time between its founding in 657 and Anno Domini 684. It has the oldest known complete song lyrics in the English language. Whatever melody it was likely sung to has not survived. The second set of lines above is the original Old English verse (with modernized spelling).