Some of the efforts to reconcile these two accounts were so fruitful as to deserve especial record. The fathers, Eastern and Western, developed out of the double account in Genesis, and the indications in the Psalms, the Proverbs, and the book of Job, a vast mass of sacred science bearing upon this point. As regards the whole work of creation, stress was laid upon certain occult powers in numerals. Philo Judaeus, while believing in an instantaneous creation, had also declared that the world was created in six days because "of all numbers six is the most productive"; he had explained the creation of the heavenly bodies on the fourth day by "the harmony of the number four"; of the animals on the fifth day by the five senses; of man on the sixth day by the same virtues in the number six which had caused it to be set as a limit to the creative work; and, greatest of all, the rest on the seventh day by the vast mass of mysterious virtues in the number seven. St. Jerome held that the reason why God did not pronounce the work of the second day "good" is to be found in the fact that there is something essentially evil in the number two, and this was echoed centuries afterward, afar off in Britain, by Bede. St. Augustine brought this view to bear upon the Church in the following statement: "There are three classes of numbers--the more than perfect, the perfect, and the less than perfect, according as the sum of them is greater than, equal to, or less than the original number. Six is the first perfect number: wherefore we must not say that six is a perfect number because God finished all his works in six days, but that God finished all his works in six days because six is a perfect number." Reasoning of this sort echoed along through the mediaeval Church until a year after the discovery of America, when the Nuremberg Chronicle re-echoed it as follows: "The creation of things is explained by the number six, the parts of which, one, two, and three, assume the form of a triangle." This view of the creation of the universe as instantaneous and also as in six days, each made up of an evening and a morning, became virtually universal. Peter Lombard and Hugo of St. Victor, authorities of vast weight, gave it their sanction in the twelfth century, and impressed it for ages upon the mind of the Church. Both these lines of speculation--as to the creation of everything out of nothing, and the reconciling of the instantaneous creation of the universe with its creation in six days--were still further developed by other great thinkers of the Middle Ages.