Engraved Gems as Seals: Power, Faith, Magic

Introduction

Gemstones depicting mythical and everyday-life scenes or magical motifs played a significant role in ancient cultures from the Bronze Age onwards. During the High and Late Middle Ages—particularly in the 12th–14th centuries—surviving gems in several Western regions were reset in engraved metal mounts to serve as seals. By examining selected gem-set seals from British collections, this blog will explore another aspect of their use: their role as amulets.

The power of stones

Gem lore, rooted in antiquity, was transmitted to the Arabs and later to the Christian world, and over the centuries, it developed, shifted, and was shaped by various cultures. The written treatises that preserved discussions of the natural and supernatural properties of stones are called lapidaries. Up until at least the 12th century, lapidaries in Western Europe were primarily shaped by Greek and Latin texts, especially those of Theophrastus, Pliny, and later the work of the Christian encyclopaedist, Isidore of Seville. An influential lapidary of this period was written by Marbode of Rennes around 1090, describing the medical qualities of about sixty stones. This tradition was later enriched by knowledge coming from the Arab world. By the 13th century, encyclopaedic works began to include more scientific and astrological reflections on stones—exploring their connections to the stars, the zodiac, and the wider structure of the universe. This intellectual development reached a high point in the lapidaries of authors such as Thomas of Cantimpré, Alfonso X, and Albertus Magnus. Alongside writings on the virtues of plants and animals, the properties of stones were seen as part of natural magic—dealing with the natural, but occult, properties of things. These doctrines were not condemned, as the supernatural qualities in nature were seen as part of God’s creation.

Figure 1: Gold ring with an unengraved sapphire, 13th–14th centuries. Gotlands Museum, Visby, Sweden, GFC9605. Photo: Ström, Göran

An inscribed gold ring, dated to the 13th–14th century, set with an unengraved sapphire (Fig. 1) and discovered outside Visby’s medieval city walls in Sweden, provides evidence that the belief in the virtues of gems extended beyond the pages of lapidaries. The Latin inscription begins on the bezel and continues around the hoop, and its translation reads as follows: “I am called sapphire; my power vanquishes poison; I wish to be called yours; once I was [the ring] of Lodovicus.” In lapidaries, sapphire was described as possessing a wide array of virtues, many related to physical well-being. Its effect against poison, however, is not typically listed under this name. A stone known as jacinth (hyacinthus), however, may at times also have been identified as sapphire. For example, Albertus Magnus wrote: “Hyacinthus is of two kinds, namely aquaticus (watery) and saphirinus (sapphire), and among other virtues, it possesses power against poison” (Wyckoff 1967: 98). Lapidaries were well known among the elite; to illustrate this, Marbode’s famous Book of Stones alone survives in about 250 copies. Most engraved gems used as seals—colourful, precious and semi-precious materials—correspond to the descriptions found in lapidary texts. This connection made each of them a potential amulet.

The power of images

While the stones’ powers were regarded as God-given, the perceived properties of the engraved images on gems were more controversial and never fully accepted by the Church. The source of the problem was that these images were not considered natural but rather imitations of nature. Not every Western medieval lapidary listed the virtues of images; those that did often warned readers that knowledge of the power of images came from ancient authors’ accounts and urged them to place their trust only in God. This may explain why lapidary authors who included descriptions of engravings sometimes told marvellous stories about the making of images in stones. Albertus Magnus’s astrological lapidary, for example, claims that one way to create images in stone is through astral power, thereby justifying both the gems and their images as natural. Many image descriptions in lapidaries can be linked to motifs engraved on ancient gems. For example, a wax seal impression of a Roman gem from The National Archives (Fig. 2) can be connected to Albertus Magnus’s description of the zodiac sign Pisces: “[…] the Fishes (Pisces), carved upon stones, by reason of the triplicity of Water and the North, temper hot dry fevers […].” (Wyckoff 1967: 141). Another example is a Roman yellow jasper gem set into a medieval seal mount from the British Museum, depicting a winged horse (Fig. 3). It can be connected to the lapidary records of Pegasus. Thomas of Cantimpré’s account, for instance, reads: “If you find a winged horse engraved on a stone, known as Pegasus, it is especially beneficial for soldiers and warriors. It grants speed and courage, and protects horses from harmful influence.” (Boese 1967: 371, trans. by the author). We must emphasise, however, that beyond lapidary readings of images, they could take on other interpretations—for instance, through a Christian lens or by being assigned different symbolic meanings.