Isaac de Vries was a son of Adolph de Vries and Vrouwtje Winnik de Jong. He married 2 June 1898 in Amsterdam to Flora Onderwijzer, a daughter of Samson Abraham Onderwijzer and Elisabeth Moses van Gelder. The couple had three children: Adolf, Elisabeth and Samson. Flora passed away on 7 July 1930 and was interred in the Jewish Cemetery in Muiderberg, (grave details C-row 37a-grave 16).
City Archive of Amsterdam, archive card of Isaac de Vries, website www.wiewaswie.nl and Akevoth/Mokum/Burial Permits.
Isaac de Vries died on 23 June 1943 in Westerbork transit camp and he was cremated on 25 June 1943. The urn with his ashes was placed on the Jewish cemetry in Muiderberg in row 37a, grave nr. 15.
Register van joden die in het kamp Westerbork zijn gecremeerd, 1943-1944; archief van de gemeente Westerbork, opgenomen in het archief van de gemeente Midden-Drenthe te Beilen, inv. n 3789