Iconographic representation of a dioptra in a flemish tapestry of the XV century

摘要

Dioptra was an optical instrument widely used in Antiquity and later in the Middle Ages. In spite of the existence of different types of dioptra, all of them have the property of helping to fix the line of sight. The so-called sighting-tube, basically an empty tube to look through, was one of the simplest types of dioptra. In the history of art there are few reported iconographic representations of this type of instrument. However, such representations are of great historical value because they help to shed light on the possible uses and types of dioptra used during these times. The hypothesis established in this article is that we have discovered such a one representation, non-previously described, at a XV century Flemish tapestry. This tapestry, called “Holly Cross Captivity”, is located in La Seo Chapterhouse Tapestry Museum in Zaragoza (Spain).