https://www.youtube.com/watch?v=3ZtCnJKih_8

I grew up listening to this song.....

The civil war song When Johnny Comes Marching Home

There was some great stuff written for/during WW1. While it might not be “officially” considered military, some of this inspired the men to sign up - for country, for mother, for their girl.

Vera Lynn - We’ll meet again

I’ll be seeing you