In the windows of the Gothic House in the Park of Dessau-Wörlitz, a landmark of the Neo-Gothic style, Prince Franz of Anhalt-Dessau incorporated his collection of stained glass paintings. The richly illustrated catalog, featuring comparative material, reveals this still largely unknown collection of stained glass from the late Middle Ages and early modern period. It arrived in Wörlitz primarily from Switzerland and southern Germany, but also from the west and north of Germany, the Netherlands, and France before 1800. This collection is the oldest, largest, and most diverse collection of stained glass of its kind still preserved in situ on the continent. The catalog not only uncovers the original context of the glass panes, most of which lack provenance information, but also the new context created by the enlightened prince. Thus, it provides insight into the intentions of the learned collector.