when a more meditative and solitary devotion – exemplified by the Devotio Moderna movement – grew in popularity. Private reflection and prayer was encouraged and the small-scale diptych fitted this purpose. It became popular among the newly emerging middle class and the more affluent monasteries across the Low Countries and northern Germany. Ainsworth says that regardless of size, whether a large altarpiece or a small diptych, Netherlandish painting is a "matter of small scale and meticulous detail". The small size was meant to entice the viewer into a meditative state for personal devotion and perhaps the "experience of miraculous visions". Late 20th-century technical examination has shown significant differences in technique and style between the panels of individual diptychs. The technical inconsistencies may be the result of the workshop system, in which the more prosaic passages were often completed by assistants. A change in style between panels can be seen, according to historian John Hand, because the divine panel was usually based on general designs sold on the open market, with the donor panel added after a patron was found. Few intact diptychs survive. As with altarpieces, the majority were later separated and sold as single "genre" pictures. In the workshop system some were interchangeable, and the religious works may have been paired with newly commissioned donor panels. Later many diptychs were broken apart, thus creating two saleable works from one. During the Reformation, religious scenes were often removed. Portraiture Secular portraiture was a rarity in European art before 1430. The format did not exist as a separate genre and was only found infrequently at the highest end of the market in betrothal portraits or royal family commissions. While such undertakings may have been profitable, they were considered a lower art form and the majority of surviving pre-16th-century examples are unattributed. Large numbers of single devotional panels showing saints and biblical figures were being produced, but depictions of historical, known individuals did not begin until the early 1430s. Van Eyck was the pioneer; his seminal 1432 Léal Souvenir is one of the earliest surviving examples, emblematic of the new style in its realism and acute observation of the small details of the sitter's appearance. His Arnolfini Portrait is filled with symbolism, as is the Madonna of Chancellor Rolin, commissioned as testament to Rolin's power, influence, and piety. Van der Weyden developed the conventions of northern portraiture and was hugely influential on