Following the death of his father, Gustav grows up in a Catholic orphanage. At twenty-six, he leaves Germany and moves successively to Italy and Spain, and then France, where he is living on the outbreak of WWII. As a German national, he is placed in an internment camp, where he starts writing and drawing. Suffering from delirium, in 1942 he is transferred to a psychiatric hospital where he continues to produce his art. Prophetic in scope, his drawings deal in a personal mythology interlarded with events from history and the Bible, two subjects he also addresses in his writings.