At this time a new danger from an unexpected quarter threatened the slowly reviving prospects of the West, and seems for the moment to have had the effect of uniting all the otherwise discordant elements for the purpose of resistance to the common foe. This was the invasion of the Saracens from the South. These warlike zealots had, after over-running and destroying the Roman civilisation of Northern Africa, passed over into Spain, and in 719 they crossed the Pyrenees and invaded Southern Gaul. The old Roman cities were at that time in a comparatively settled and prosperous condition, when their tranquility was thus rudely interrupted. The whole country was devastated by the Saracen invaders, the towns were besieged, and in most cases taken and destroyed. We shall find, as we proceed, that there is scarcely one which does not bear the mark of the destructive hand of the Saracen. The overwhelming flood was, however, at length stemmed by Charles Martel in 732 at Tours, when the Moors were completely defeated and driven back beyond the Pyrenees. This great victory gave repose for a time; and thinking men being weary of the long night of Anarchy which had so long oppressed them, began to look round for some principle by which rule and order might again be restored. Any durable and fixed system would be better than the fluctuation and uncertainty so long experienced. After so many changes and so much diversity of government, the principle of unity naturally presented itself to men’s minds. The tyranny of the Empire was forgotten under the more crushing oppressions of all kinds which had since had to be submitted to; while its unity and strength were remembered, and people began to long for what now appeared to be “the good old times” of the Empire. It was agreed that the only satisfactory form of government was one which, like the Empire, should include the whole Roman world. This was considered to be in accordance with the nature of things. As there is one God, so there should be one Emperor to represent Him on earth as temporal ruler, and one Pope to represent Him in matters spiritual as the head of the Church. And by a remarkable coincidence this idea came to be realised about A.D. 800, in the person of Charlemagne, who extended his sway over nearly the whole of Western Europe. What rendered possible at that time the apparent fulfilment of the dream of universal temporal and spiritual government, was the fact that during Charlemagne’s time these two powers recognised that they could be of considerable service to one another, and were consequently on very friendly terms. As Charlemagne was now the supreme temporal Emperor, so the Bishop of Rome had also fully established his supremacy in the Church. This had been brought about by various fortunate circumstances--by his occupying the See of the great city whose name was still a power, and where the Bishop held the old municipal authority and