Passage: Petrus Christus placed his sitter in a naturalistic setting rather than a flat and featureless background. This approach was in part a reaction against van der Weyden, who, in his emphasis on sculptural figures, utilised very shallow pictorial spaces. In his 1462 Portrait of a Man, Dieric Bouts went further by situating the man in a room complete with a window that looks out at a landscape, while in the 16th century, the full-length portrait became popular in the north. The latter format was practically unseen in earlier northern art, although it had a tradition in Italy going back centuries, most usually in fresco and illuminated manuscripts. Full-length portraits were reserved for depictions of the highest echelon of society, and were associated with princely displays of power. Of the second generation of northern painters, Hans Memling became the leading portraitist, taking commissions from as far as Italy. He was highly influential on later painters and is credited with inspiring Leonardo's positioning of the Mona Lisa in front of a landscape view. Van Eyck and van der Weyden similarly influenced the French artist Jean Fouquet and the Germans Hans Pleydenwurff and Martin Schongauer among others.The Netherlandish artists moved away from the profile view – popularised during the Italian Quattrocento – towards the less formal but more engaging three-quarter view. At this angle, more than one side of the face is visible as the sitter's body is rotated towards the viewer. This pose gives a better view of the shape and features of the head and allows the sitter to look out towards the viewer. The gaze of the sitter rarely engages the viewer. Van Eyck's 1433 Portrait of a Man is an early example, which shows the artist himself looking at the viewer.  Although there is often direct eye contact between subject and viewer, the look is normally detached, aloof and uncommunicative, perhaps to reflect the subject's high social position. There are exceptions, typically in bridal portraits or in the case of potential betrothals, when the object of the work is to make the sitter as attractive as possible. In these cases the sitter was often shown smiling, with an engaging and radiant expression designed to appeal to her intended.Around 1508, Albrecht Dürer described the function of portraiture as "preserving a person's appearance after his death". Portraits were objects of status, and served to ensure that the individual's personal success was recorded and would endure beyond his lifetime. Most portraits tended to show royalty, the upper nobility or princes of the church. The new affluence in the Burgundian Netherlands brought a wider variety of clientele, as members of the upper middle class could now afford to commission a portrait. As a result, more is known about the appearance and dress of the region's people than at any time since the late Roman period. Portraits did not generally require lengthy sittings; typically a series of preparatory drawings were used to flesh out the final panel. Very few of these drawings survive, a notable exception being van Eyck's study for his Portrait of Cardinal Niccolò Albergati.
Output: What is the first name of the person who is credited with inspiring the positioning of the Mona Lisa?