Izak Kalker, butcher by trade, was a son of Mozes Levie Kalker and Rachel Meijer, was born on 2 March 1883 in Varik in the municipality of West Betuwe. On 12 July 1921 he married Maria van Blijdenstijn in Ophemert, a daughter of Hijman van Blijdenstijn and Judith Docters. She was born on 5 January 1890 as the third child in a family of six.
The Kalker couple lived with their children at Waalbrandi…