Testimonio Editorial has chosen to edit facsimiles of several of the best conserved beatus. Escorial &.II.5, Seo de Urgel, Valladolid University (970), the Royal Academy of History (San Millán de la Cogolla C10-11), the National Historical Archive (Tábara C10) and Turin (C12). By so doing, Testimonio is seeking not only to commemorate the value of the splendid miniatures in these manuscripts, but also the fact that the Commentary on the Apocalypse of St John is an essentially Spanish genre which was of great importance in the high Middle Ages, especially in the Kingdom of León. The original Commentary was attributed to a cleric named Beatus who lived in Asturias around 800, and who was well known for his fiery attacks on the Adoptionist heresy, maintained by Bishop Elipando of Toledo and Bishop Justo of Urgel. His work on the Commentary was in fact a compilation based on previous works on the same theme, that is, various interpretations of St John’s Apocalypse, of which the most important was that by a North African named Ticonius. Over the years, new elements were added to the basic Beatus commentary, so that by the 10th century, it became a fixed structure, with a general prologue, a summary commentary on the Apocalypse, St Jerome’s Commentary on the Book of Daniel, Isidore of Seville’s Etymologies, a few short definitions of the codex or book and a number of genealogical tables of biblical figures. From the 10th century onwards, it became customary to include within the text of the Commentary, and then in the Book of Daniel, miniatures based closely on the biblical text, illustrating the passage from the Apocalypse being commented on. It is these illuminations which set the Beatus copies apart from other Visigothic codices (with the exception of a few bibles, etc.) and which have made them famous. The most important copies are those which belong to the great León School, also known as the Mozarabic School, which was created during the 10th century by scribes and miniaturists of the calibre of Magius, Senior, Emeterius, Ende, Oveco and others, and which has its own particular characteristics, such as the colour tones and the use of different colour bands to give perspective to the pictorial composition. The great Beatus copies are all in Visigothic script. Nevertheless, when this script was replaced by Carolingian, copies continued to be made using the new script and then, later, Gothic. Around 15 manuscripts (complete or fragments) have survived from this period, such as the magnificent copy executed in Gerona in the 12th century, conserved today in Turin. These late works respect the accepted structure of the earlier models but the miniatures evolve so that the architecture, furniture, human figures and clothing depicted reflect the period of their execution.