Crux gemmata

A crux gemmata (Latin for jewelled cross) is a form of cross typical of Early Christian and Early Medieval art, where the cross, or at least its front side, is principally decorated with jewels. In an actual cross, rather than a painted image of one, the reverse side often has engraved images of the Crucifixion of Jesus or other subjects.

Examples in metalwork are the Cross of Justin II (6th century, in the Vatican Museums), the 'crumpled cross' in the Staffordshire Hoard (8th century), the Cross of Lothair (10th century, Aachen Cathedral Treasury), the Iberian Cross of the Angels (808) and Victory Cross (908), and the Cross of Cong (1120s?, National Museum of Ireland).

In the Late Antique and early medieval periods, many objects of great significance, such as reliquaries, were studded with jewels in a style that in recent centuries has been restricted to crowns and other coronation regalia and small pieces of jewellery. In the case of the cross, such decorative embellishment was especially common, and the jewelled cross is a specific type that was represented in paint, mosaic, carved ivory and other media. Jewelled crosses were also carved in stone, e.g. the Shandwick Stone with the jewels represented by bosses.

The cross very often has splayed ends to its arms, but the proportions of the vertical axis to the horizontal one depends entirely on the needs of the composition, and varies greatly. Pendilia, or hanging jewels or ornaments, may hang from the arms, especially the letters alpha and omega shaped in gold. The motif is first seen in a sarcophagus fragment from the late 4th century; the splayed ends of the arms are present from the earliest examples.

In depictions of the cross, such as that in the mosaic in Santa Pudenziana, Rome (384–9), the jewelled cross stands on a hill or mound with a backdrop of a panoramic view representing Jerusalem, with the cross itself representing the New Jerusalem or "heavenly city". The jewelled cross also served as a symbol of the Christian version of the Tree of Life, especially when the arms are shown putting out shoots from their corners. The Staffordshire Hoard 'crumpled cross' has vine leaves showing at the corners and represents Jesus the vine. It is sometimes shown on a mound representing paradise, with four rivers flowing down it (the four rivers were understood as representing the Four Gospels); a stepped base represents the hill in actual crosses or more confined depictions. The link of the cross generally with the Tree of Life appears frequently in the hymns of Venantius Fortunatus. Sharp (2016) has shown the interlace on the front of the Staffordshire Hoard cross corresponds with the river or tree of life described in Revelation 22. 1–2.

The use of large jewelled crosses as processional and military crosses stems from the victory of Constantine over his rival Maxentius at the Battle of the Milvian Bridge outside Rome in 312 AD. The vision of Constantine led to his having a large golden gem-studded processional cross made and the adoption of the cross as a standard by Christian armies.

For much of the period, a large jewelled cross is recorded as decorating the presumed site of the Crucifixion, around which the Church of the Holy Sepulchre had been built. It was presented by the Eastern Emperor Theodosius II (reigned 408–450). The Empress Helena, mother of Constantine in the early 4th century allegedly discovered part of the True Cross, at a time when interest in the cross was increasing, in part due to its use as a standard by the Roman Army under Constantine her son.

The paradox whereby the instrument of execution is rendered the vehicle of Christ's triumph in the Resurrection remains to the present day a central theme in Christian devotion, and the jewelled cross was one of its first visual manifestations.