Adriaan Meerkamp van Embden solved the puzzle. He noted that during Claes' lifetime, not a single Van Borselen owned land in Brigdamme. The first to do so was Claes' son Gerard. Therefore, Claes was not lord of Brigdamme. Claes I's grandson Claes II did own two-thirds of Brigdamme in the 1390s. Obviously Claes II had been confused with his grandfather. Meerkamp van Embden also annulled the claim that Claes I had founded Popkensburg Castle. All this cut Claes down to size, but the fact that two wealthy Van Borselen branches sprang from Claes does make it likely that Claes amassed quite some wealth.
