 Nineteenth century art historians including Viollet-le-Duc, Focillon, Aubert, and Max Dvořák contended that this is one of the most universal features of the Gothic style.Religious teachings in the Middle Ages, particularly the writings of Pseudo-Dionysius, a 6th-century mystic whose book, "De Coelesti Hierarchia", was popular among monks in France, taught that all light was divine.When the Abbot Suger ordered the reconstruction of choir of the his abbey church at Saint-Denis, he had the builders create seventy windows, admitting as much light as possible, as the means by which the faithful could be elevated from the material world to the immaterial world.