Where did Hercule Poirot come from?

Belgium, yes, and Agatha Christie's brain, yes.

But also maybe this guy:

A real-life Belgian policeman who came to the West Country as a refugee during the first world war has been tipped as a possible inspiration for one of the literary world's most famous fictional detectives, Hercule Poirot.

Regardless of whether it's true or not, suddenly I feel like re-reading some Dame Agatha.