My ancestor Antoni Triebs was according to his marriage record (Groningen, Netherlands, 1718) "van Calaats uijt Boheemen", translated: from Calaats from Bohemia.
I've tried to find a town with a matching name, without result.
Bohemia could be either Bohemia proper (modern-day Western en Central Czechia) or the lands of the Bohemian Crown (modern-day Czechia and Silezia in Poland).
Calaats would be something like Kalác in Czech spelling. The pronunciation is about /kala:ts/ in the International Phonetic Alphabet.