Willem was born in post-war Rotterdam to an Italian father who owned a demolition business and a Dutch mother whose family ran a grocery store. Growing up in a city being rebuilt from the devastation of war, Willem’s early experiences influenced his art, particularly his memories of the flat wasteland and the skeletal remains of buildings. He spent his childhood exploring museums, studying art, and cycling to coastal spots, all while being deeply influenced by his paternal and maternal heritage, which connected him to both Renaissance and Dutch masters.

Willem often included his wife, Pauline, in his works. A poet herself, Pauline and Willem would create side by side in the same room. She would frequently read her poetry aloud, never certain if Willem was truly listening. But then she would glance at his canvas and discover that he had subtly woven elements of her poetry into his compositions, reflecting a deep, silent connection between their creative worlds.