Christiaan Dames, SV/PROG

Marriage: https://www.familysearch.org/ark:/61903/3:1:3Q9M-C91K-J3SS-N?i=63&c...

Marriage register https://www.familysearch.org/ark:/61903/3:1:3Q9M-C91K-J3SS-N

About this person, I know from what I have learned from my long deceased mother (be it only a family legend or not) that his surname was something more Latinic sounding (something like Dumas, from one of the Romance languages), but that he had changed it to the much moreGermanic sounding Dames. Him being from Italy (Venice) that seems quite possible to me.
Then his first nname, Christiaan, would probably also originally have been Christo-whatever.
But now, for me, the first name of his father seems to cast a questionmark over the whole theory.
Were these people truly from Italy or not and how did this Chrstiaan end up in the Cape?
Has Christiaan Dames' true history been recorded somewhere?
Goethe Johannes du Toit Olwagen, g5 (grandmother on mother side was born Dames)