The cathedral, when completed, was but a third in size and grandeur of the original design, for the Black Death fell upon Siena and carried off her builders in the midst of their work; yet it remains magnificently arresting to modern eyes, as though the faith of those who planned and fashioned its slabs of black and white marble for the love of God and their city had breathed into their workmanship something of the mediaeval soul. The same is true of ‘Nôtre Dame de la Victoire’ in Paris, founded by Philip Augustus, of which Victor Hugo says ‘each face, each stone, is a page of history’. It is true of nearly all mediaeval churches that have outlived the ravages of war and fire, memorials of an age, that if it lagged behind our own in ultimate achievement, was pre-eminent in one art at least--ecclesiastical architecture. Where the architect stopped the mediaeval sculptor took up his work, at first with simple severity but later in a riot of imagination that peopled façades, vaulted roofs, and capitals of columns with the angels, demons, and hybrid monsters that haunted the fancy of the day. The flying buttress, the invention of which made possible lofty clerestories with vast expanses of window, brought to perfection another art, the painting of glass. Here also the mediaeval artist excelled, and the crucibles in which he mixed the colours that hold us wrapt before the windows of Leon, Albi, and Chartres, still keep unsolved the secret of their transparent delicacy and depth. [Sidenote: Learning and Church Organization] In the architecture, the sculpture, and in the stained glass of the Middle Ages we see original genius at work, but in learning and culture Europe was slower to throw off the giant influence of Rome. Even under the crushing inroads of barbarian ignorance Italy had managed to keep alive the study of classical authors and of Roman law. Latin remained the language of the educated man or woman, the language in which the services of the Church were recited, sermons were preached, correspondence carried on, business transacted, and students in universities and schools addressed by their professors. The advantages of a common tongue can be imagined: the comparative ease with which a pope or king could keep in touch with bishops or subjects of a different race; the accessibility of the best books to students of all nations, since scarcely a mediaeval author of repute would condescend to employ his own tongue: above all perhaps the ease with which an ambassador, a merchant, or a pilgrim could make himself understood on a journey across Europe, instead of torturing his brain with struggles after the right word in first one foreign dialect and then another.