Greetings to all, and apologies if this subject was covered somewhere that I neglected to look for it.
I checked the previous forum entries, but there was no answer to my specific question.

I'm wondering about a phrase used in the chorus of The Fighting 69th...

The second line goes:
"Singing 'Here's to the boys who fear(ed) no noise,
They're the Fighting 69th'"

Does this business about the "noise" refer to anything?
It seems an odd turn of a phrase...

I wondered if there were something related to the Civil War,
or the time period in general which might be behind it.

Thanks in advance to all who reply!