Han van Meegeren (October 10, 1889 to December 30, 1947) was such a talented forger of old masters paintings that even after his conviction for forgery, and his death, experts continued to argue over the authenticity of his work. It was Meergern, if I recall, that argued during the trial that by selling a Vermeer that would end up in Goring's hands, selling to the Nazi invader, a fake Vermeer, that he, Meergeren, was acting as a Dutch patriot. What no one has tallied is the number and identification of all his fake products.
Han van Meergeren also deliberately produced kitsch to sell, to get by in his youth. Here is an example:
This sketch is titled "Jongen met poes." "Boy with Cat" is a pencil drawing, dated 1916. Meergeren's art today fetches a high price.