dominated the northern European market. Their popularity was in part due to the production of more affordable, single leaf miniatures which could be inserted into unillustrated books of hours. These were at times offered in a serial manner designed to encourage patrons to "include as many pictures as they could afford", which clearly presented them as an item of fashion but also as a form of indulgence. The single leaves had other uses rather than inserts; they could be attached to walls as aids to private meditation and prayer, as seen in Christus' 1450–60 panel Portrait of a Young Man, now in the National Gallery, which shows a small leaf with text to the Vera icon illustrated with the head of Christ. The French artists were overtaken in importance from the mid-15th century by masters in Ghent, Bruges and Utrecht. English production, once of the highest quality, had greatly declined and relatively few Italian manuscripts went north of the Alps. The French masters did not give up their position easily however, and even in 1463 were urging their guilds to impose sanctions on the Netherlandish artists. The Limbourg brothers' ornate Très Riches Heures du Duc de Berry perhaps marks both the beginning and a highpoint of Netherlandish illumination. Later the Master of the Legend of Saint Lucy explored the same mix of illusionism and realism. The Limbourgs' career ended just as van Eyck's began – by 1416 all the brothers (none of whom had reached 30) and their patron Jean, Duke of Berry were dead, most likely from plague. Van Eyck is thought to have contributed several of the more acclaimed miniatures of the Turin-Milan Hours as the anonymous artist known as Hand G. A number of illustrations from the period show a strong stylistic resemblance to Gerard David, though it is unclear whether they are from his hands or those of followers. A number of factors led to the popularity of Netherlandish illuminators. Primary was the tradition and expertise that developed in the region in the centuries following the monastic reform of the 14th century, building on the growth in number and prominence of monasteries, abbeys and churches from the 12th century that had already produced significant numbers of liturgical texts. There was a strong political aspect; the form had many influential patrons such as Jean, Duke of Berry and Philip the Good, the latter of whom collected more