Jonas van Dam was born into a Groningen family with seven children, one of whom died very young. Like his father and most of his siblings, he was in the textile business. He first worked as a rag dealer, then as a dealer in second-hand clothing and eventually he had his own clothing workshop in Amsterdam and later in Haarlem (Barrevoetstraat 15 and then Gedempte Oude Gracht 78). In this trade he had a lot of competition from family members who were also active in the textile trade. Since they were all called van Dam, this could be confusing for customers. That is why Jonas frequently placed advertisements in which he pointed out to his customers that J. van Dam's clothing store was not only the best, but also the cheapest. To avoid misunderstandings, he printed his own portrait. On January 11, 1912, Jonas van Dam married Rebecca (Bep) Mok. They had two children: Elisabeth (Elly) in 1918 and Joseph in 1921. In May 1925, Jonas and Rebecca divorced. Both remarried. Their daughter Elisabeth died in hiding in 1944. Joseph fled to England via France, Spain and Portugal and survived the war. In the early autumn of 1942, Jonas admitted himself to the Provincial Hospital in Santpoort to go into hiding. It is unknown what happened to him when this hospital was evacuated in January 1943. He may have gone into hiding elsewhere and was betrayed, because on 11 May 1943 he was registered in Westerbork. On 18 May 1943 he was transported to Sobibor, where he was killed immediately upon arrival.
