The representation of Agnus Dei in this brooch appears to combine features from The Adoration of the Lamb in the apse mosaics of two Roman churches, Santi Cosma e Damiano and San Clemente. The halo round the head of the lamb consists of a solid plaque of gold,while the glass tesserae reproducing the lamb’s fleece are cut as white crescent forms. Its head reveals a combination of curved and rectangular white and brown tesserae, the eye meticulously denoted in deep ochre and black. The lamb stands on slender green tesserae while the background consists of a diaper pattern of gold alternating with deep red, and combinations of blue and green. The ground is traversed diagonally by the extraordinarily slender white staff surmounted by the cross which the Lamb holds in its right frontal paw.
The decorative four-petalled border appears to derive from a seventh century Lombardic brooch originating from Southern Italy which was owned by Castellani and sold by the firm to the British museum in 1865. This is one of the most sophisticated examples of micromosaic work to be seen in Castellani’s oeuvre. A parallel example is in the British Museum collection depicting Agnus Dei without the cross. It is reproduced in the catalogue of the touring exhibition ‘Castellani and Italian Archaeological jewellery’, held at the Bard Graduate Center for Studies in the Decorative Arts, Design and Culture, the National Etruscan Museum of Villa Giulia, Rome, and the Gilbert Collection, Somerset House, from 2004-2005.
See Chapter six, ‘Micromosaics and their Sources’ by Judy Rudoe, pages 153-178.