“The Spanish Forger is the name given to an unidentified individual who, in the late 19th to early 20th century, created a large number of forgeries of medieval miniatures.
The Spanish Forger’s works were painted on vellum or parchment leaves of genuine medieval books, using either blank margins or scraping off the original writing. He also “completed” unfinished miniatures or added missing miniatures in medieval choir books. His works fooled many experts and collectors and appear today in the collections of many museums and libraries. Over 200 forgeries have been identified. 
Although he was originally thought to be Spanish, it is now believed he may have been French, working in Paris. A number of his forged miniatures have been identified as copied, with modifications, from those published in several French books published in the 1870s -1880s.”(http://en.wikipedia.org/wiki/Spanish_Forger)