It was published between 1923 and 1938 in Dutch, French, English and Italian - he completed 17 of the 21 volumes he had planned, with Frederick Mason Perkins and his widow Charlotte van Marle completing the work and producing the 19th volume and the general index.
Born in the Hague to a Hungarian mother and a father of distant Picard descent (hence his surname Marle), he moved to Paris in 1906.
His first writings dealt with medieval Dutch history - in 1908 he published Le Comté de Hollande sous Philippe le Bon and in 1916 a Dutch-language study of Meister Eckhart (De mystieke leer van Meister Eckhart).
From then on he wrote several studies on Italian painting, collaborating with the Bollettino d'Arte and other international specialist journals.
The racial hatred of Fascist Italy led it to be hostile to foreign art historians and so after his death in Perugia he was buried not there but in distant Pozzale, a district of Pieve di Cadore.