With the support of his parents, Rein abandoned his studies in Vienna, and in 1925 returned to his family, which in the meantime moved to Zagreb.

[3] With having excellent knowledge of foreign languages, particularly French, Rein quickly turned to an artistic life.

[2] The Spanish Civil War deeply shocked Rein, as he joined the international anti-war movement that opposed the emerging Fascism.

[3] Due to the frequent persecution of Croatian Jews, Rein escaped to Gorski Kotar, but in 1942 he ended up in the concentration camp Kraljevica.

His sister was the only member of the family who survived the Holocaust, and after the war she moved to Canada where she lived until her death.

In the early 1980, after reanimation, research, through the exhibitions and monographs devoted to Rein, his saved works were presented to wider audience.