Boy I love this place. This seemed like such a standard drinking song I never wondered about the origins (I had it from the Clancy Brothers too)... and I had a little mondegreen for a while, since they pronounce Boldly and Coldly as if they had a few more syllables than we Americans use, I heard them dying as hot or cowardly... even though I had understood bowedly to mean boldly, go figure.

Fascinating stuff, do tell more.