From the book The Burdens of Sister Margaret by Craig Harline

Klosterarbeiten – translated from the German it means Monastery Work. These little altars or shrines were among the most stylish items in Catholic devotion of the time. Developed in the fifteenth century, and perfected by nuns and beguines who often worked in tandem with lay painters and woodcarvers, such shrines came to the Low Countries by way of Brugge around 1500 and spread from there. Some were in the form of a triptych, as most altarpieces, but much smaller, perhaps thirty-nine inches high by fifty inches wide. The wings, usually painted by professionals, portrayed saints or benefactors of the house and order. But the central portion was the crucial and distinguishing part, for it was usually fashioned by the nuns themselves, and often stood alone. It consisted of a fairly shallow case full of meticulously carved figures – saints, angels, biblical characters, and so on – which were then adorned with a wagon full of carefully crafted artificial flowers, usually from silk or parchment or even metal. Situated behind a small fence that might stand amid imitation grass, here was the hortus conclusus, or enclosed garden, which was not only the usual symbol of Mary’s virginity but also the place where the inspiring characters portrayed – and by implication the chaste viewer as well – could best work out salvation.

Besides the general artistic significance of the little altars, they likely reflected as well a distinctively female way of expressing religious feeling or artistic prowess in this time – for cloistered women inevitably restricted worship to their home convent, while the better-traveled male religious might worship in a multitude of places during his life and possess less motive or opportunity for the careful embellishment of his house. Indeed, a comparison of decoration in male and female convents and parish churches, may lead to the detection of genuinely different attitudes between the genders about form and manner of worship.