The concept of the Celts and their identity has been the subject of much debate in the last three decades, especially among British prehistorians. The historiographical complexities have been explored in the work of John Collis and Michael Morse, but other issues remain to be more fully examined, such as the difference between categories and identities, the situationally constructed nature of such concepts and the types of social identities to be expected in prehistoric Europe. There is, however, a general consensus about the changing meaning of the term ‘Celts’, and the problems inherent in any attempt to align language, material culture and social identity.

These questions were the focus of a major exhibition organised by the British Museum and National Museums Scotland, at the British Museum from September 2015 to January 2016, before moving to Edinburgh for March to September 2016. It was not an exhibition of Celtic art, rather an attempt to deconstruct the term and to show that there were many Celtic arts, often reworking old motifs, frequently innovating, and always responding to changing social circumstances. Such an attempt to use changing artistic styles to illustrate changing social identities is a hugely ambitious challenge.

The exhibition (seen in London: Edinburgh hosted a modified version) won rave reviews from the national newspapers, and quite rightly: it was a superb display of visually stunning objects, many the product of complex technological skills, beautifully and informatively displayed. The arrangement was chronological, from the Early Iron Age to the twentieth century. The largest element was the art of the pre-Roman Iron Age and, thanks to the wealth of the museums’ collections and the generosity of other museums, especially in Germany and Denmark, it allowed us to see many of the star names of the canon: Glauberg, Klein Aspergle, Basse Yutz, Waldalgesheim, Nebringen. The Iron Age gallery upstairs had also been denuded, bringing together the major British finds, but though objects such as the Wandsworth helmet and the Battersea shield may be familiar, they have never been better displayed: full marks to the team who designed the display and lighting. Alongside familiar items there were newer finds, including a Crownthorpe cup, the Blair Drummond hoard and the very recent Bredgar coin die. The massed material from Snettisham was a real eye-opener, but the most spectacular exhibit, and also the most problematic, was the Gundestrup cauldron. It was found in a bog in Denmark, but has strong Thracian affinities and was almost certainly made in south-eastern Europe; other elements, however, such as torc, carnyx and horned god, can be paralleled in the Celtic art of the Iron Age. It has figured in most books on Celtic art, but it is still unclear in what sense it can meaningfully be called Celtic; rather, it raises the question whether such ethnic attributions are appropriate in a world where there was free movement of goods and ideas.

As the frequency of Celtic art on the Continent declined in the late Iron Age, so the geographical focus switched to Britain, where it enjoyed a new lease of life, typified by the distinctively regional mirrors: should we think of continuity or renewal and revival in new social conditions? A further transformation came with the Roman conquest, but it is not a simple story of Romanisation or an art of opposition: Celtic swords are found in Roman forts, Celtic motifs are common on Roman metalwork, and beyond the frontier in Scotland a new style of massive personal ornaments was developed. Celtic art was clearly being revived again in several different ways in the changed social circumstances.

For the late Roman to medieval periods, the focus was inevitably on Scotland and Ireland, mainly the former. The further transformation of the art in the early Christian period with the introduction of exotic motifs such as interlace and the presence of many religious objects demonstrating the arrival of Christianity is visually striking, showing a different art for a different context. Different again was the survival of a form of Celtic art in parts of Scotland in the medieval period, emphasising a Gaelic identity.

A large section towards the end of the exhibition was devoted to the modern rediscovery of the Celts and their recent reworking. Antiquarian promotion of the word Celtic is difficult to explain visually, but that is not so with the Romantic discovery of bards and druids or the nineteenth-century pattern books that popularised an Early Christian form of Celtic art. The juxtaposition of bardic chairs, the work of Glasgow artists such as Henry and Hornel's stunning painting of The Druids bringing in the mistletoe and a tea set by Archibald Knox shows the variety of responses. Another response was the use of early historic heroes for nationalistic purposes: no room for Boudicca in her chariot, of course, but Caratacus was there, in the form of Foley's forceful statue, as was Cuchulain. Perhaps the least successful part of the exhibition was the attempt to demonstrate modern versions of Celtic identity, despite film of St Patrick's Day in remote places; maybe in the future museums will collect the material culture of the Celtic diaspora and the adoption of Celtic identity.

The book to accompany the exhibition, edited by two of its co-curators, is not so much a catalogue as a list of objects with a series of lavishly illustrated essays to develop the argument. The controversy over Celtic identity receives brief treatment, with even less devoted to recent discussion of the nature of art; the meaning of the art of the prehistoric period is also admitted to be entirely a matter of speculation, unlike that of later periods. Instead, the argument seeks to show that there were many Celtic arts, each responding to its social context, and to address a more answerable question about the use of decoration in enhancing objects that played significant roles in important spheres of cultural practice.

The prehistoric and early Roman section is largely written by Hunter, with contributions from Farley and Jody Joy and Ian Leins, both of whom were involved in the original organisation of the exhibition before leaving the British Museum. The earliest examples of Celtic art appear mainly on objects associated with warfare, horses and chariots, feasting and personal adornment, suggesting what the important ideologies of early Iron Age society were. From the third century b.c., however, the use of art declined, except on coins and some pottery, and gold was used for coinage not personal adornment; these changes coincided with the emergence of large religious sanctuaries and oppida, clearly indicating a major change in social organisation, though how much was due to the rise of Rome may be debated. The argument is persuasive and the art emerges as a material response adopted by human agents in specific social circumstances.

Thereafter the argument seeks to show the successive reworkings or revivals of a series of Celtic arts, each with an eclectic repertoire of motifs, sometimes using earlier Celtic themes, frequently introducing new ideas from outside. Hunter's discussion of the impact of Rome emphasises the diversity of ways in which Celtic motifs were adapted in various media inside and outside the Empire, frequently paired with classical themes in a way that makes it difficult to decide if a particular pattern is Celtic or classical. The late Roman and early Christian chapters are by Martin Goldberg, the third of the co-curators. They continue the argument, contrasting the immediately post-Roman reuse of Roman-Celtic ideas and Roman silver with the very different art that emerged from a.d. 600 onwards, as new kingdoms emerged and Christianity provided a new context for art in the form of religious objects as well as a new network for the transmission of exotic ideas. There is not space here to do justice to the scholarly chapters on the medieval period and on the recent Celtic revivals, by Heather Pulliam and Frances Fowle respectively, but they provide excellent accounts of material that may not be so familiar to prehistorians and Romanists.

The idea behind this project was intellectually ambitious, but the exhibition and the book together have largely succeeded in offering a vision, not of Celtic art as the essential product of a timeless people, but of a series of Celtic arts responding eclectically to changing circumstances over 1,500 years. They have also shown how the decorated objects that we choose to celebrate as art can be meaningfully integrated into a wider archaeological discussion of material culture in past societies.