Such was the part--a characteristic part--played by Paris in the Revolution of 830. Four years later Paris appears playing an opposite, yet a no less characteristic part. The Emperor Lewis, already restored and again deposed, is held as a prisoner by his eldest son Lothar, and is led in bonds to Paris.[52] Again the men of the East, the faithful Germans, are in arms for their sovereign under Lewis, at that moment his only loyal son. But by this time the city has changed sides. Lothar, for fear of the German host, flees to the South, leaving his father at liberty; the late captive is led by his rejoicing people to the minster of Saint Denis, and there is girt once more with the arms of the warrior and with the Imperial robes of the Cæsar.[53] Once then in the course of its long history, did Paris behold the inauguration of a lawful Emperor. But it was the re-inauguration of an Emperor whom one Parisian revolution had overthrown, and whom another Parisian revolution had set up again; and in the moment alike of his fall and of his restoration the force of loyal Germany forms at one time a threatening, at another an approving, background. We thus see Paris, well-nigh unheard of during the reign of Charles the Great, suddenly rise into importance under his son. Under Charles the Bald its importance becomes greater still, and it begins to assume the peculiar function which raised it to the head place in Gaul. The special wretchedness of the time was fast showing the great military importance of the site. Under the rule of the Austrasian Mayors and Kings there had been endless wars, but they had been wars waged far away from Paris. Above all, no hostile fleet had for ages sailed up the Seine. Lutetia on her island must, under the Frankish power, have enjoyed for some generations a repose almost as unbroken as she had enjoyed in the days of the _Roman Peace_. Now all was changed. The Empire was torn in pieces by endless civil wars, wars of brother against brother, and the fleets of the Northmen, barely heard of in the days of Charles the Great, were making their way up the months of all its rivers. Men now began to learn that the island city, encompassed by the broad Seine, with its bridges and its minsters, and the Roman palace on the left bank, was at once among the most precious possessions and among the surest bulwarks of the realm. It is not without significance that the one time when the Great Charles himself visited Paris, it was in the course of a progress in which he had been surveying the shores of the Northern Ocean.[54] He came to Paris as a mourner and as a pilgrim, yet we may believe that neither his grief nor his devotion hindered him from marking the importance of the post. His eye surely marked the site as one fated to be the main defence, if not of his whole Empire, at least of its western portion, against the pirate-barks by which the Ocean was beginning to be covered. And probably it was not mere accident that it was in the course