ym aster ▁was ▁Max ▁Fried man . ▁ ▁Through ▁him , ▁he ▁came ▁to ▁know ▁" L ud wik " ▁( Ign ace ▁Re iss ). ▁In ▁June ▁ 1 9 3 7 , ▁he ▁drew ▁a ▁study ▁of ▁Re iss ▁on ▁the ▁back ▁of ▁a ▁menu ▁for ▁a ▁later ▁b ust . ▁ ▁Family ▁K rop ▁was ▁the ▁son ▁of ▁Henry ▁K rop , ▁b aker , ▁and ▁Johann a ▁Louis a ▁Cord es . ▁ ▁He ▁had ▁two ▁brothers ▁and ▁four ▁sister s . ▁ ▁K rop ▁married ▁Freder ika ▁Wille mina ▁(" M ien ") ▁S le ef ▁on ▁December ▁ 2 4 , ▁ 1 9 1 4 . ▁ ▁They ▁had ▁two ▁children , ▁a ▁daughter ▁and ▁a ▁son . ▁ ▁A ▁third ▁child ▁( son ) ▁died ▁young . ▁ ▁His ▁father - in - law ▁J . ▁W . ▁S le ef ▁was ▁a ▁typ ograph er , ▁a ▁prominent ▁member ▁of ▁the ▁Dutch ▁social ist ▁party ▁and ▁som etime ▁chairman ▁of ▁the ▁Amsterdam ▁section ▁of ▁the ▁social ist ▁SD AP ▁party . ▁ ▁Through ▁this ▁family ▁connection , ▁K rop ▁came ▁into ▁contact ▁with ▁left ist ▁organizations ▁and ▁thought . ▁ ▁Works ▁in ▁Amsterdam ▁ ▁Mercur ius ▁en ▁de ▁wind stre ken ▁( 1 9 1 6 – 1 8 ), ▁Tele fo ond ienst , ▁Her eng racht ▁( K amer ling h ▁On nes la an ) ▁Gra ve ▁of ▁Albert ▁H ahn ▁( 1 9 1 8 – 1 9 ), ▁N