Jacob Roos was a son of Levie Roos and Sara Binger. He was born in Rotterdam on 11 December 1884, had already three siblings: Roosje born in 1880, who has been killed in Auschwitz on 6 September 1944; Heiman born in 1881 but who died already on 4 February 1882, just four months old and Maria born in 1882, of whom place and date of death is (still) unknown. After the birth of Jacob in 1884 another …