Medieval manuscript illuminations are a precious and irreplaceable part of our cultural heritage. Throughout extensive research, it was proved that the materials used for the illuminations are fundamental for provenance and dating studies, as well as to comprehend the cultural and technological context and connection between these objects. In this PhD project, the focus will be on medieval manuscripts of royal production of Iberian origin: the Ajuda Songbook and four manuscripts produced in Alfonso X scriptorium, including the Songs of Holy Mary. Through the in-depth research on their main organic colourant, Brazilwood, and the molecular characterization of the colour palette used, resorting to portable instrumentation, it will be unveiled the possible material, technological and cultural connection between both scriptoria. The knowledge acquired for the Alfonsi manuscript, a scriptorium of well-known place and date of origin will help understand and answer, through comparison, where Ajuda Songbook was possibly produced.