Isaac Spier was a son of Simon Benjamin Spier and Esther de Sterke. He married Helena Hartog in 1888 in Amsterdam. She died in 1924. They had two children.
Addition of a visitor of the website
In addition, a Jokos file (number 002757) on this person is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.