songs of Brunanburh and Maldon,[70] the day when the young king Lewis led the West-Frankish host to victory over the heathen,[71] stands out well-nigh alone in the records of that unhappy time. While neither realm was spared, while one set of invaders ravaged the banks of the Seine and the Loire, while another more daring band sacked Aachen, Köln, and Trier,[72] the rival Kings of the Franks were mainly intent on extending their borders at the expense of one another. Charles the Bald was far more eager to extend his nominal frontier to the Rhine,[73] or to come back from Italy adorned with the Imperial titles,[74] than he was to take any active step to drive out the common enemy of all the kindred realms. At last the whole Empire, save the Burgundian Kingdom of Boso, was once more joined together under Charles the Fat. Paris was again under the nominal sovereignty of an Emperor whose authority, equally nominal everywhere, extended also over Rome and Aachen. Precarious and tottering as such an Empire was, the even nominal union of so many crowns on a single head, however unfit that head was to bear their weight, does seem to have given for the moment something like a feeling of greater unity and thereby of greater strength. Paris, defended by its own Count and its own Bishop, was defended by them in the name of His Emperor, Lord of the World.[75] The sovereigns alike of East and West were appealed to for help, and at least a show of help was sent in the name of both parts of the Frankish realm.[76] The defence of Paris was essentially a local defence, waged by its own citizens under the command of their local chiefs. Still the great check which the invaders then received came nearer to a national act on the part of the whole Frankish Empire than anything which had happened since the death of Charles the Great.