This work is an attempt—whether successful or not the critic must decide—to give a concise summary of the facts at present available for forming a theory as to the origin and development of Celtic art in Great Britain and Ireland. By Celtic art is meant the art of the peoples in Europe who spoke the Celtic language, but it must always be borne in mind that although linguistically they were Celts, yet racially they were of mixed Celtic and Iberian blood, so that their art was possibly quite as much Iberian as Celtic. It is only since the epoch-making discoveries of Schliemann in Greece, of Flinders Petrie in Egypt, and of Arthur Evans in Crete that it has been possible in a satisfactory manner to connect the culture of Britain in the Bronze Age with the corresponding culture on the Continent. It is now quite clear that certain characteristic decorative motives, such as the divergent spiral, are of foreign origin instead of having been invented in Ireland, as was at one time believed. Other discoveries made in England, more especially those at Aylesford, Glastonbury, Mount Caburn, and Hunsbury, have thrown an entirely new light on the archæology of this country by showing that the Early Iron Age began here two or three centuries at least before the Roman occupation. Lastly, the explorations made by Continental antiquaries at Hallstatt in Austria, La Tène in Switzerland, and in the Gaulish cemeteries of the Marne district in France, point to the sources of the culture to which the late Sir Wollaston Franks gave the name “Late-Celtic.” Celtic art naturally divides itself into two distinct periods, the Pagan and the Christian. With regard to the latter, the remains have been so fully investigated that it is hardly probable any new facts will be brought to light which will seriously alter the conclusions now arrived at. With regard to the Pagan period the case is altogether different, as most of the finds hitherto made have been due to accident, and until the large number of inhabited and fortified sites belonging to this period are systematically excavated our knowledge must necessarily remain incomplete. I have endeavoured to give in the footnotes all the sources whence my information has been obtained, but I should like more especially to acknowledge my indebtedness to A. Bertrand and S. Reinach’s _Les Celtes dans les Vallées du Pô et du Danube_; J. Anderson’s _Scotland in Pagan Times_ and _Scotland in Christian Times_; Arthur Evans’ papers on the Aylesford, Æsica, and Limavady finds in the _Archæologia_; and George Coffey’s papers on the ornament of the Bronze Age, Newgrange, etc., in the _Journal of the Royal Society of Antiquaries of Ireland_, and in the _Transactions_ and _Proceedings of the Royal Irish Academy_.