Izaak David de Leeuw was a son of David Abraham de Leeuw and Hendrika van Kreveld. He married Sophia Hamburger in 1890 in Alkmaar. She passed away in 1909 in Leiden.
Addition of a visitor of the website
In addition, a Jokos file (number 60464) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.