But whatever may have been the causes which produced the distinguishing features of Netherlandish painting, we have still to enquire the origin from which the practice of painting in northern Europe proceeded. For in taking Melchior Broederlam as a starting-point we are only going as far back--with the exception of certain rude wall paintings--as the earliest examples take us; and having seen how in Italy the whole history of the art is traceable to Cimabue, Duccio, and Giotto, through the Byzantines, at least a century before Broederlam comes under our notice, we might naturally conclude that it was from Italy that it spread to Cologne, and from Cologne to the Netherlands. So far as is known, however, this was not the case, and we must look elsewhere than to Italy for the influences which formed this school. Nevertheless it was a collateral branch of the same stock--Byzantine art--and the family resemblance comes out none the less strongly from the two branches having developed under different circumstances. In Italy, as we have seen, the Byzantine seed, sown in such fertile soil, attained suddenly a great luxuriance. In the north, transplanted by Charlemagne to Aix-la-Chapelle in the ninth century, it grew slowly and more timidly, but none the less surely, under the cover of Monasticism, in the manuscripts illuminated with miniatures; and thus when it did burst forth into fuller blossom, the boldness of the Italian masters, who worked at large in fresco, was wanting, and a detailed and almost meticulous realism was its chief characteristic. Another point worth noticing is that though primarily introduced for religious purposes, as in Italy, namely the decoration of the cathedral erected by Charlemagne at Aix-la-Chapelle, the paintings in his palace showed forth events in his own life, such as his campaigns in Spain, seiges of towns and feats of arms by Frankish warriors. At Upper Ingelheim, likewise, his chapel was adorned with scenes from the Old and New Testaments, while the banqueting hall exhibited on one wall the deeds of great Pagan rulers, such as Cyrus, Hannibal, and Alexander, and on the other those of Constantine and Theodosius, the seizure of Acquitaine by Pepin, and Charlemagne's own conquest over the Saxons and finally himself enthroned as conqueror. Although no trace remains of these paintings, contemporary manuscripts executed by his order are still in existence in the libraries of Paris, Treves, and elsewhere from which we can form some idea of the style in which they were rendered and of the source from which they were derived.