The Codice Calixtino, an illustrated manuscript in twelfth century, has disappeared from the Cathedral in Santiago de Compostela, local authority said Thursday. The Codice Calixtino used to work as a guide to pilgrims making the journey to the city of Santiago de Compostelain in the middle age. The beautifully illustrated book included introduction and advice, as well as sermons, miracles and associated religious writings. The Codice Calixtino is made up of five books and two appendices and is widely considered as one of the most important works of Spain\'s religious and artistic heritage with an incalculable value. The book was kept in a sealed chamber and protected by an alarm system in the Cathedral. Its disappearance was first noticed by one of the workers responsible for the Cathedral archives at 8 P.M. Tuesday. After three hours of searching he notified the police of the disappearance. Early indications were that the book had been stolen, possibly by an organized band who could be working under orders of a specialized collector, but as yet no further details have emerged.