He was a regular contributor to the historical magazines Oud Holland and Künstler-Inventare. In 1922, he left the Netherlands for health reasons and settled in Monaco, publishing books in 1927 on Jan Steen and in 1935 a catalog of Rembrandt paintings, often referred to in the literature as "Bredius 1935". He bequeathed his papers to the Rijksbureau voor Kunsthistorische Documentatie, and his art collection lives on in the Museum Bredius.