Madonna of Bruges), Ghent (where he admired van Eyck's Ghent altarpiece), and Zeeland. Dürer took a large stock of prints with him and wrote in his diary to whom he gave, exchanged or sold them, and for how much. This provides rare information of the monetary value placed on prints at this time. Unlike paintings, their sale was very rarely documented. While providing valuable documentary evidence, Dürer's Netherlandish diary also reveals that the trip was not a profitable one. For example, Dürer offered his last portrait of Maximilian to his daughter, Margaret of Austria, but eventually traded the picture for some white cloth after Margaret disliked the portrait and declined to accept it. During this trip he also met Bernard van Orley, Jan Provoost, Gerard Horenbout, Jean Mone, Joachim Patinir and Tommaso Vincidor, though he did not, it seems, meet Quentin Matsys. Having secured his pension, Dürer returned home in July 1521, having caught an undetermined illness, which afflicted him for the rest of his life, and greatly reduced his rate of work. Final years, Nuremberg (1521–1528) On his return to Nuremberg, Dürer worked on a number of grand projects with religious themes, including a crucifixion scene and a Sacra conversazione, though neither was completed. This may have been due in part to his declining health, but perhaps also because of the time he gave to the preparation of his theoretical works on geometry and perspective, the proportions of men and horses, and fortification. However, one consequence of this shift in emphasis was that during the last years of his life, Dürer produced comparatively little as an artist. In painting, there was only a portrait of Hieronymus Holtzschuher, a Madonna and Child (1526), Salvator Mundi (1526), and two panels showing St. John with St. Peter in background and St. Paul with St. Mark in the background. This last great work, the Four Apostles, was given by Dürer to the City of Nuremberg—although he was given 100 guilders in return. As for engravings, Dürer's work was restricted to portraits and illustrations for his treatise. The portraits include Cardinal-Elector Albert of Mainz; Frederick the Wise, elector of Saxony; the humanist scholar Willibald Pirckheimer; Philipp Melanchthon, and Erasmus of Rotterdam. For those of the Cardinal, Melanchthon, and Dürer's final major work, a drawn portrait of the Nuremberg patrician Ulrich Starck, Dürer depicted the sitters in profile. Despite complaining of his lack of a