Petrus grew up in the Netherlands and studied literature at the University of Utrecht; painting and printmaking at the Royal Academy of Fine Arts, The Hague. He moved to Dorset in 1998, worked as artist and manager of the arts at Salisbury Hospital, until he and his partner, singer/composer Helen Porter, set up Gresham House Studios in East Cornwall. The Fortune of the Seventh Stone (2016) was shortlisted for the Holyer an Gof awards, and presented at the 2017 North Cornwall Book Festival. Now a British citizen, Petrus divides his time between art, writing, teaching, building, and development work for the arts charity Endelienta.