The predatory expeditions and wars of conquest of military Celtic tribes in search for new homes for their superfluous populations brought into prominence the deities of war, as was the case also with the ancient Romans, themselves an agricultural and at the same time a predatory race.  The prominence of war in Celtic tribal life at one stage has left us the names of a large number of deities that were identified with Mars and Bellona, though all the war-gods were not originally such.  In the Roman calendar there is abundant evidence that Mars was at one time an agricultural god as well as a god of war.  The same, as will be shown later, was the probable history of some of the Celtic deities, who were identified in Roman times with Mars and Bellona.  Caesar tells us that Mars had at one time been the chief god of the Gauls, and that in Germany that was still the case.  In Britain, also, we find that there were several deities identified with Mars, notably Belatucadrus and Cocidius, and this, too, points in the direction of a development of religion under military influence.  The Gauls appear to have made great strides in military matters and in material civilisation during the Iron Age.  The culture of the Early Iron Age of Hallstatt had been developed in Gaul on characteristic lines of its own, resulting in the form now known as the La Tene or Marnian type.  This type derives it name from the striking specimens of it that were discovered at La Tene on the shore of Lake Neuchatel, and in the extensive cemeteries of the Marne valley, the burials of which cover a period of from 350-200 B.C.  It was during the third century B.C. that this characteristic culture of Gaul reached its zenith, and gave definite shape to the beautiful curved designs known as those of Late-Celtic Art.  Iron appears to have been introduced into Britain about 300 B.C., and the designs of Late-Celtic Art are here represented best of all.  Excellent specimens of Late-Celtic culture have been found in Yorkshire and elsewhere, and important links with continental developments have been discovered at Aylesford, Aesica, Limavady, and other places.  Into the development of this typical Gaulish culture elements are believed to have entered by way of the important commercial avenue of the Rhone valley from Massilia (Marseilles), from Greece (via Venetia), and possibly from Etruria.  Prehistoric archaeology affords abundant proofs that, in countries of Celtic speech, metal-working in bronze, iron, and gold reached a remarkably high pitch of perfection, and this is a clear indication that Celtic countries and districts which were on the line of trade routes, like the Rhone valley, had attained to a material civilisation of no mean character before the Roman conquest.  In Britain, too, the districts that were in touch with continental commerce had, as Caesar tells us, also developed in the same direction.  The religious counterpart of this development in civilisation is