Christianity was introduced into Ireland mainly from Roman Britain during the fifth century AD, around the time of the collapse of the Roman Empire.

The resulting exposure to new influences meant that new styles and technical skills were acquired and added to the repertoire of Irish craftsmen. It was a time of economic and social change in which the Church played a major role. Christian rituals required special objects such as eucharistic chalices, patens and containers for the enshrinement of books and relics, and these were fashioned and adorned by Irish craftsmen.

The collections are rich in high quality metalwork, much of it of an ecclesiastical nature. The quality of what was produced, especially during the eighth to ninth centuries, has led to these centuries being referred to as a Golden Age.

Some objects that were produced at this time have become iconic treasures, such as the Ardagh Chalice, Derrynaflan Chalice and Paten, Moylough Belt Shrine and the ‘Tara’ Brooch.

Less well known treasures include the Tully Lough Cross, found offshore of a small crannóg in Co. Roscommon; a small, decorated metal bucket from a crannóg in Clooneenbaun, Co. Roscommon; and two wooden buckets with ornate metal mounts from Clonard, Co. Meath and Derrymullen, Co. Laois.

Small tomb-shaped shrines used to venerate the bones of saints have survived, with relatively complete examples found in the rivers Shannon and Erne. A collection of mounts decorated in the Ultimate La Tène style from Donore, Co. Meath are likely to be from a larger tomb-shaped reliquary that would have been carried in procession with the aid of carrying poles. From the monastery of Dromiskin, Co. Louth there is a small stone reliquary inside of which there was a little wooden box containing metal objects, including a key.

Early medieval craftsmen were skilled stone carvers who produced a series of splendid high crosses bearing biblical scenes.

There are also a number of carved stone slabs bearing cross designs from monastic sites including particularly fine examples from Inishkea North, Co. Mayo. A pillar stone from Aglish, Co. Kerry bears a cross design but it also carries an inscription written in the ogham alphabet, the earliest alphabet used to write in the Irish language. The Aglish Stone is one of around two dozen pillar stones in the collection that carry ogham inscriptions.

Personal adornment appears to have been of great importance and the collection contains numerous examples of pins and brooches of various types and made from a variety of materials. These are mainly bronze, but also include examples made from silver, gold, iron, bone and antler. Glass and enamel was used to decorate brooches and pins, and many beads and bracelets made from class are in the collection as well as bracelets made from lignite. Decorated metal finger rings are also represented. A variety of craft tools associated with metalworking, carpentry and farming activities provide a broad insight into the life of the people, while iron swords and spears attest to the violence of the times.

The arrival of the Vikings at the end of the eighth century began a period during which monasteries were attacked and many church treasures were looted or destroyed. However, the Vikings were traders as well as raiders and their commercial activities brought large amounts of silver into Ireland, some of which has been discovered in ingot hoards. The Vikings also introduced new types of objects and novel art styles, which led to developments in native metalwork and decorative arts. The easy availability of silver during the ninth and 10th centuries led to new fashions in brooch design with bossed-penannular, thistle and kite-shaped brooches being the popular forms.

During the 11th and 12th centuries there was a Renaissance in Irish metalwork that drew heavily on the Viking Ringerike and Urnes art styles. Notable treasures of the period are the croziers from Kells and Lismore, the Shrine of St Lachtin’s Arm and the shrine made around 1100 AD to house a bell associated by tradition with St Patrick. Perhaps the best known treasure of the later period is the Cross of Cong whose principle patron was Turlough O’Conor, King of Connacht and High King of Ireland.