Early Flemish painting was contemporary to the development of the early Renaissance in Italy. In the middle of the 15th century Italy and Flanders were the most important artistic centres in Europe because of their constant innovations. This situation would not have been possible if it had not been accompanied by economic and social developments. In Flanders, the most distinguished cities were Ghent, Bruges and Ypres because they all formed links with the commercial networks that joined northern Europe to western Europe. The region made up the Duchy of Burgundy, whose governors, the dukes, had been patrons of Gothic art. In 1477 the Duchy was passed over to the Austrian crown of Habsburg, because of its economic importance. The Spanish Habsburg dynasty started with Charles I of Spain and V of the Austrian Empire, which meant that Spanish Renaissance and Baroque art were very closely related to Flemish styles. Flemish painting did not have a tradition of large-scale paintings, with the exception of stained glass windows. However, it did have a long tradition of exceptional quality miniatures. This determined some aspects of Flemish art, such as the use of bright colours, which echoed the pigments used in the miniatures. Attention to detail was another aspect that was transmitted to large-scale paintings from these miniature masterpieces. This feature was largely made possible by the advances in oil painting techniques. Oil painting was already used but its lengthy drying was a great disadvantage and restricted its use considerably. Flemish painting of this period always depicted a scene that referred to the landscape, either through a window or because the painting was a direct outdoor scene. These landscapes were done without taking preliminary sketches from life, which meant their elements were completely stereotyped. The rocks were jagged and with no vegetation, coloured towns with jutting towers were depicted in the distance, trees were feather-shaped, with long thin trunks, and so on. Figures were distributed in a balanced way, either in the centre if there was only one or symmetrically if there were more. The action was very restrained and hardly left room for movement. Flemish painting differed from Italian painting in that it showed absolutely no interest in Classical Antiquity. This led Flemish works to be described as "alla moderna" and the Quattrocento paintings as "alla antiqua" because they imitated Ancient Greece and Rome. The Flemish did not tend to theorise about their discoveries or about the personalities of their artists. There are hardly any treaties on Flemish painting from the period or biographies on the era's most important artists. This lack of theoretical elaboration responded to a spiritual vocation: whilst the Italians attempted to renew world knowledge using human measures, such as science and reason, the Flemish were guided by a religious or spiritual experience of the visible. This was to such an extent that alchemy, highly developed in this period, rather than being a method of chemical research, was considered a metaphysical proposal of the integration of man in the divine universe. The philosopher's stone was not only the object that transmuted material into gold, but also the living symbol of Christ. This meant that the capturing of space had an experimental quality about it, a process of trial and error. The Flemish discovered linear and aerial perspective at the same time as the Italians, but in an empirical way not via mathematical or optical developments. Such techniques permitted an extremely naturalistic representation of the world, saturated with spiritual symbols. A field covered with flowers could in fact be a complex allegory of the Virgin or theological virtues. An image that might seem completely secular and removed from religious reflection might in fact be a sanctification of visual reality. Flanders was one of the first regions where portraits were done that penetrated the sitter's character. The typical Flemish portrait, which was later took hold in Spain for centuries, depicted the figure less than half-length, slightly turned to the side rather than frontally, against a dark neutral background, and with some symbol on their face or in their hands. The fact that the person was slightly turned meant they were involved in the space, which was not represented by tricks of furniture or architectural background. Only the presence of the figure against a lost background insinuated the existence of volume and space. The most perfect portraits were those done by Roger van der Weyden, the Van Eyck brothers, Hugo van der Goes, Petrus Christus and Dieric Bouts. They were magnificent exponents of this reality that was not actually very real, but was rather half way to the spiritual world. There are marvellous examples of their work in Spain, as Spanish royalty greatly admired their work. The Museo del Prado is remarkable for its collection of Flemish art, such as the altarpiece of the Descent from the Cross by Van der Weyden.