On the date and contents of a Portuguese medieval technical book on illumination: O livro de como se fazem as cores

The book this article discusses is a late medieval Portuguese technical text on illumination written with Hebraic characters. It belongs to a miscellaneous manuscript at Parma's Biblioteca Palatina. Discovered in 1803, it was attributed to Abraham ben Judah Ibn Hayyim and dated to 1262. Soon some authors assigned it to the fifteenth century. The paper's water-marks, recently observed, confirmed the fifteenth century date. Yet, the possibility that this text could be a copy of an older original remains. However, the discussion of the historical context and the content also suggests that the original dates more probably from the fifteenth than the thirteenth century. In terms of structure and content this text should not be considered a treatise but a heterogeneous compilation which, besides the Hebraic marks, presents significantly alchemic, Castilian and Arabic influences.