Pelagius also had all judicial documents relating to the diocese collected and copied into a massive cartulary called the "Liber testamentorum" or "Libro (gótico) de los testamentos", compiled around 1120, possibly at the monastery of Santos Facundo y Primitivo in Sahagún. Though it contains falsified, forged, and interpolated documents designed to buttress the claims of Oviedo, otherwise it remains an important compilation for historical research. It is illustrated with colourful miniatures in the Romanesque style, and is the most important monument to this period in the history of painting in Spain.