A (, in Irish "cover") or book shrine is an elaborate ornamented metal reliquary box or case used to hold Early Medieval Irish manuscripts or relics. They are typically later than the book they contain, often by several centuries. In most surviving examples the book comes from the peak age of Irish monasticism before 800, and the extant cumdachs date from after 1000, although it is clear the form dates from considerably earlier. The majority are of Irish origin, with most surviving examples now in the National Museum of Ireland (NMI). The usual form is a design based on a cross on the main face, with use of large gems of rock crystal or other semi-precious stones, leaving the spaces between the arms of the cross for more varied decoration. Several were carried on a metal chain or leather cord, often worn off the belt, or suspended around the neck, placing them next to the heart and thus offering spiritual and perhaps medical benefits (the same was done with the St Cuthbert Gospel in a leather bag in medieval Durham). They were also used to bring healing to the sick or dying, or more formally, as witness contracts. Many had hereditary lay keepers from among the chiefly families who had formed links with monasteries. Only five early examples of survive, including those of the Book of Dimma and Book of Mulling at Trinity College, Dublin, and the Cathach of St. Columba and Stowe Missal. Of the St. Molaise Shrine, only the Gospels are extant; the casing is lost, but more often the reverse is the case. Other books such as the Book of Kells, Book of Armagh and Book of Durrow are known to have once had either or treasure bindings or both, but as they contained valuable precious metals they were a natural target for looters and thieves. Characteristics and formats The format and function of may derive from book caskets used by early Christian Romans. Both types were intended to protect sacred text or relics, and it is plausible that Irish monasteries would seek to emulate the prestige and, according to the Irish art historian Rachel Moss, "splendor of Roman liturgical ceremonies". The Irish church emphasised relics that were, or were thought to be, objects frequently used by monastic saints, rather than the body parts preferred by most of the church, although these were also kept in local