This song I heard for the first time (shamed flush) on Star Trek, TNG. Soon after (surprise, surprise) it became a popular song around the campfires. There seems to be a strong crossover audience between Trek and SCA/Faire/etc...
The best rendition I've heard is by Trelane the Bastard and friend (Sorry, the name is lost in my memory) as an acapella.
The minstrel boy, to the war has gone,
In the ranks of death you will find him.
His father's sword he has girded on,
And his wild harp slung behind him,
"Land of Song", said the warrior bard,
"Though all the world betrays thee,
One sword, at least, thy rights shall guard,
One faithful harp shall praise thee!"
The minstrel fell! But the foe-man's chain
Could not bring his proud soul under;
The harp he loved ne'er spoke again,
For he tore its cords asunder
And said "No chain sully thee
Thou soul of love and bravery!
Thy songs were made for the pure and free,
They shall never sound in slavery!"