Marcus Salomon de Jong was a son of Salomon Alexander de Jong and Roosje Vischschraper. He married Rachel Koen in Amsterdam on 23 October 1901, a daughter of Salomon Abraham Koen ane Sara Berlijn. The couple had three children: Salomon, Roosje and Sara. Only Roosje has survived the Holocaust. Salomon lost his life somewhere in Mid Europe on 4 February 1945 and Sara has been killed in Sobibor on 11 June 1943. Marcus Salomon de Jong and his wife Rachel have been killed both in Sobibor on 16 July 1943.
City Archive of Amsterdam, archive card of Marcus Salomon de Jong and website www.wiewaswie.nl.