This matter of the early intermingling of Celts and Germans in northern Mid-Europe will be afterwards seen to have a special interest in reference to the Celtic colonisation of Britain and Ireland. Before concluding the evidence I have to bring forward on the subject, it will make the drift of the matter clearer if I state the later outcome of the Celtic migrations northward among the Germanic population. We have already seen that, as archaeologists are agreed, the Celts north of the Alps were in possession of iron long before the use and manufacture of iron was established in the more northern parts of Europe. It is mainly to this advantage that we may ascribe the predominance acquired by the Celts among the Germans. In the German regions, however, the Celts were for the most part an ascendant minority. Their domination must have lasted for several centuries. A time came when, in those parts which in the Celts were numerically and otherwise in greatest strength, a fusion of peoples took place, resulting in a Celto-Germanic population, Celtic in language but mainly Germanic in race. Meanwhile, the less blended section of the Germans, retaining their native language, had acquired the craft of ironwork, and were advancing in civilisation and no doubt increasing at the same time in numbers. Eventually the German-speaking Germans became more powerful than the once dominant Celtic minority and more powerful also than the Celto-Germanic folk who had become Celtic in language. A sense of distinct nationality grew up between the two populations. The Celticised Germans were located in western Germany, towards the Rhine, the un-Celticised Germans farther east. Under hostile pressure from the German-speaking element, the Celtic-speaking element were forced westwards across the Rhine into Gaul. Here they in turn pressed back the Celts who had settled in north-eastern Gaul, and modern events will help to fix in the mind the fact that this overflow of Celto-Germans into Gaul extended as far west as the river Marne, where it was brought to a stand by the resistance of the earlier Celtic inhabitants. The date of this migration was probably later than that of the battle of Clastidium, 222 B.C., when, as we have seen, the Celts appear to have still held sway over the Germans. The Celto-Germanic settlers between the Rhine and the Marne were the Belgae of Cæsar's time. At first sight, this account may seem to be too precise an effort to fill up a blank in history, but the testimony of Cæsar and Tacitus, witnesses of prime authority, seems to leave no room for any alternative view.