According to family lore, the Gassmann name around Stuttgart derives from two brothers who immigrated from the south (some say Switzerland, others Northern Italy) and settled, respectively, in Untertürkheim and Fellbach, then two independent villages, today suburbs of Stuttgart.
In trying to verify this story, I found the following, although I am not sure of its authenticity:
Jakob (or Johann) Gassmann was born in 1646, married Anna Schönhaar in Untertürkheim in 1664 and died in Untertürkheim in 1693. I am doubtful of this, because I know that all the past church records in Untertürkheim were destroyed in 1693. I do not know the source for the wedding date and location.
The earliest mention of a Gassmann in Fellbach is in 1664, when Hannss Gassmann married Maria Magdalena Jutzler on November 15th.
This is certainly consistent with the family lore, but that, of course, is not proof. I am trying to walk the timeline back a little bit, and in particular I am interested in establishing a family relation between Jakob (or Johann) and Hannss Gassmann. If the family tale is true, I have to look to the south for records, but I do not know what sources there might be in Switzerland and/or Northern Italy. Is there anything available on the internet? What else is out there that I might consult?