I'm unsure. I'm also S47 and am of German ancestry.
I'd guess spread by Romans? Though Gauls seems to be a remote possibility considering some migrated east to the Balkans during classical antiquity.
Z56 is mainly Italic, but likely not entirely so, as certain subclades within it seem to show up more in places like Britain and Germany, but there probably isn't enough of a sample size to say how the distributions of these clades will play out yet.
