I won't go through all the sources now that more or less show that the father of Cornelia "Neetlje" Classen/Claessen (and various spellings) who married Isaac van Sintern is Cornelius Claessen (and various spellings) as it seems to be generally accepted. Remember, two the daughters who married into the Kolb family are Magdalena and Sarah (I am descended from their father Isaac a total of 5 times) were married respectively to Martin Kolb and Jacob Kolb (sons of Thielman Kolb). Food for thought... In my person by person lookup of will extracts, this popped up: CLAESEN, CORNELIUS. September 30, 1708. October 23, 1708. C. 139. Daughter Catherine Beerens of Philadelphia., widow and her four children names not given. Administrator: Katherine Beerens. Witnesses: Jacob Gaetschalck, Isaac van Sintern and Hannah Kasdorp. Any discussion of note? Incidentally regarding patronyms, it would imply that Cornelius' father's first name here would be Claes. We do know however that the daughter of Cornelius Classes, ie, Cornelia, had 4 daughters, but the daughter (a widow) mentioned here is Catherine Beerens. Michel