 He also noted that the bright white walls made it more difficult to appreciate the colours of the stained glass windows, and declared that the work violated international conservation protocols, in particular, the 1964 Charter of Venice of which France is a signatory.The President of the Friends of Chartres Cathedral Isabelle Paillot defended the restoration work as necessary to prevent the building from crumbling.At the beginning of the 11th century, Bishop Fulbert besides rebuilding the cathedral, established Chartres as a Cathedral school, an important center of religious scholarship and theology.