But this is not the whole of the story. The very strength and efficiency of Henry’s government were sure to produce a reaction in favor of feudal liberties in which his sons serve simply as convenient centres of crystallization. Only time could unify each of these dominions internally, while far more time was required to consolidate them into a permanent kingdom, and these processes were interrupted when they had barely begun. Such a solution of the ultimate problem of consolidation was, we have seen, entirely possible and even natural; but another was possible and also natural, namely the union of these territories under the king of France. Geography, as well as history, favored the second alternative. * * * * * The geographical unity of France is one of the most obvious facts on the map of Europe. The Alps and the Pyrenees, the Mediterranean and the Atlantic, are its natural frontiers; only on the northeast are the lines blurred by nature and left to history to determine. Within these limits there are of course many clearly marked subdivisions--the valleys of the Rhone, Garonne, Loire, and Seine, Gascony, Brittany, Normandy, Flanders, and the rest--which formed the great fiefs of the Middle Ages and the great provinces of later times. Sooner or later, however, as population increased, as trade and commerce developed, and as the means of communication were strengthened, these divisions were certain to draw together into a single great state. Where the centre of the new state would lie was not a matter of accident but was largely determined by the great lines of communication, and especially by the commercial axis which runs from the Mediterranean to Flanders and the English Channel. On this line are situated the Roman capital of the Gauls, Lyons, and the modern capital, Paris. This fact, combined with the central and dominant position of the Paris basin in relation to the great valleys of the Seine, the Loire, and the Meuse, established the region about Paris, the Ile-de-France of history, as the natural centre of this future nation. Such a state might grow from without toward its centre, as the modern kingdom of Italy closed in on Rome, but the more natural process was from the centre outward, as England grew about Wessex or Brandenburg about the region near Berlin. In the great contest between Capetian and Plantagenet the Capetian “held the inner lines.” Shut off from the sea on the side of the Loire as well as on the side of the Seine, he was in a position to concentrate all his efforts to break through the iron ring, while the Norman rulers had to hold together the whole of their far-spread territories against reaction and rebellion at home as well as against the French at Tours and LeMans and in the Vexin. Meanwhile up and down these valleys the influences of trade, commerce, and travel were at work breaking down the political barriers and drawing the remoter regions toward the geographical centre.