The Millowitsch theater dynasty reaches back until to the 18th century in the 7th generation. (The direct ancestors of the dynasty let itself read on the Internet, but these are then only the respective theater owners). The oldest puppeteer was Franz Andreas Millowitsch (1793-1875). Josef Caspar Millowitsch (1830-1867) then took over after this the theater. If "your" Nicolaus Millowitsch is born 1825, then Franz Andreas Millowitsch had probably other sons yet. "Your" Nicolaus then is descended from one of the other sons. However, can tell you only the family chronicle of the family Millowitsch perhaps exactly this. (I think, Willy Millowitsch had probably a family chronicle). The name Millowitsch is not a German surname. Therefore you will find him in the phone book also only 1 times in all of Germany: of the theater in Cologne! It is suspected that this name is "Germanized". The real name shall be "Milovic". And this is a typical surname of the area of Yugoslavia. The Millowitsch family shall have walked through the places once to earn money there with her travelling theater. The travelling theater then had established itself in Cologne later. By the way: Had Nicolaus emigrated? Or why are you interested at that?