Hello. I am Jonas Gustainis from Lithuania. the oldest Gustainis known to our family is my great-great-great-great grandfather with an unknown first name.
my grandfather Vincas Gustainis says that the first Gstainis' generations were very noble and lived in Germany. that makes sence, because "gust" is a german word for "mist" and "stein" (i think lithuanians changed it to "stain") means "rock".
i'm afraid there were no Jurgis, Valentine or Anthony among our ancesters as my family tree shows. but it's nice to know there are more people with the same last name from other counrties :)

p.s. this question might seem a bit idiotic and random, but do you or some one in your family has a thing called tourette's syndrome, or some kind of tics?