My late Grandfather's name. He emigrated to the United States in the 1980s and there got the nickname 'Ziggy' (pronunciation issues no doubt). Nowadays a very rare name in Poland especially for young people, although in recent years people have started to name babies with very old traditional names.
Both me and my wife had Polish great-great-grandfathers named Zygmunt. (I'm half Polish and my wife is a quarter Polish.) I've always liked it a lot better than Sigmund, since Zygmunt doesn't have the Freud association.