My own memory is so short these days. The last line I remember is, " we fight and do not FEAR to die" Sounds very militant. I seem to remember a chorus singing it. Melody is very simple. Sol-do-re-mi-mi (repeat), sol-do-re-mi-sol fa mi, sol-sol-sol -ti-ti (repeat) sol-sol-sol-ti-la-fa-mi-do. Wouldn't win any prizes. I never know why old songs pop into my head.
Your suggestion of origin is interesting. If the song fades out of my head, well, that happens as often as they come in.
I am going to be 82 soon. I don't think senior dementia is on me, but who knows?