Hieronymus Bosch is a kind of populist superstar among the old-master painters. His fans relish his surreal, inventive images of the afterlife, but particularly his vivid visions of hell: sinners straddling giant knife-blades, egg-shaped machines churning miscreants into their bellies, cruel hybrid frog-devils and dog-faced lizard birds.

Five hundred years since the death of the Dutch artist in 1516, it’s believed that only a tiny fraction of Bosch’s output survives — about two dozen paintings and some 20 drawings — but the fascination with his oeuvre hasn’t abated. In all that time, aficionados have asked the same question: How did he come up with his amazing imagery? Where did he get the inspiration for these strange little monsters?

Very little is known about Bosch the man. We have no letters or diaries, and written information in archives tends to be about transactions: who bought what and when. I wondered what I could discover about his mind and his artistry by going back to the place where he was born, lived and worked.

I headed to the city of ’s-Hertogenbosch, known locally as Den Bosch, whose name the artist eventually took as his own. This year the city celebrates the 500th anniversary of the death of its legendary son, in an attempt to “forever link Bosch to Den Bosch,” as I was told by Lian Duif, program manager of the Jheronimus Bosch 500 Foundation, a nonprofit organization that has been planning the quincentennial celebration since 2008.