Isaac Boas was a son of Alexander Boas and Rachel Koen. He married on 15 December 1915 to Clara Waterman, daughter of Meijer Waterman and Sara van Praag.
From the first marriage of his father to Catharina Walvisch, solomnized on 7 May 1873 in Amsterdam, Isaac had three more brothers: Barend (who passed away in 1936 and who was married Klaartje Roet, Jochem and 545132|Salomon)), who were unmarried…