It's originally Irish, "Johnny - I Hardly Knew Ye". And it makes a whole lot more sense. His wife hardly knew him, he had a "queer (odd) look" (war had changed him). His legs were gone, and more.

When did the Yankees change it to "Johnny Come Marching Home Again?" Sorry, but stuff like that bugs me. Now I won't rest until I find out.

I don't want my few Irish friends to blame me. It was them Union/Yankees that did it. They can't do nothing for themselves. Bunch of plagiarist.