Only a few decades after the conquest of Gaul by Caesar the power of the free Celtic tribes in central Europe collapsed as a consequence of their finding themselves placed, during the course of the 1st century B.C., in an insecure position between the Romans and the Germans pressing down from the North. The victorious Alpine campaign of Drusus and Tiberius in 15 B.C. sealed the fate of, among others, the Vindelicians who occupied the south German area north of the Alps as far as the Danube. Here, still today, mighty hillforts bear witness to the power of those nameless Celtic chieftains who caused them to be erected. Contemporary literary sources tell all too little about the history of this area and about the cultural connections of its inhabitants before the Roman occupation. Therefore modern research relied upon Caesar’s description of the Gallic tribes in drawing parallels between the large late La Tène hillforts in central Europe and the city-like tribal centres of the Gauls in France, which Caesar called ‘oppida’ or even ‘urbes’.

Recent investigations at the Lateran by the present writers, with the indispensable collaboration of Professor Enrico Josi, and under the auspices of the Pontifical Institute of Christian Archaeology, have added considerably to our knowledge of the Constantinian basilica. The 4th-century foundation walls of this church are easily identifiable. They consist of massive baulks of concrete made principally with big fragments of grey-white marble which are obviously the product of the breaking-up of some quite important building, since pieces of architectural mouldings, capitals, ashlar, etc., frequently appear. During the past century (the first significant excavations date from 1851) such foundation walls have been exposed in many places, and an extensive system of vaults has been formed beneath the floor of the church as one investigation after another has added to our knowledge of the Constantinian building; to say nothing of the earlier structures on top of which the basilica was built, namely the Castra Nova Equitum Singularium of the early 3rd century, and certain rich private mansions which lie at a still lower level.

The mirror is likely to have come from a lady’s grave: no details of the find are available. There is in the parish a well-known cemetery dating from the beginning of the Early Iron Age.

The overall length of the mirror with its handle (PLATE XXVI) is 23·5 cm. (11·75 in.); the diameter of the plate is 16·3 cm. (8·15 in.). This has a delicate incised line round its circumference, close to the edge, back and front, as the photographs show.

The face of the mirror is smooth and glossy: the piece suffered some damage when disclosed—probably by a plough-share. It is thus slightly bent at the top (losing, here, its smooth reflecting surface), and the handle has been wrenched, causing a crack in the plate to the right and above it. It should be noted that there is no loss of detail of the pattern on the mirror-back resulting from this crack: the dark strip on the photograph (PLATE XXVII) is, in part, a shadow cast by lateral displacement.