Isaäc van Praag was a son of the diamond cutter and later grocery store owner Wolf van Praag and Marianna Koopman. He was born on 16 July 1891 at Waterlooplein 78 in Amsterdam. Later in life he ran a butter and cheese business but later became a goldsmith by profession. On 21 July 1921, he married Sara Coe, the eldest of the three children of Isaac Marcus Coe and Betje Wittenburg. Sara was born in…