When the news of Theodoric’s defeat reached the king it found him, as before stated, in camp in the centre of Bavaria. The war with the Avars was prospering, but it was still a long way from completion. To deal with two enemies in such widely separated regions as Hanover and Hungary was a hard problem for a commander-in-chief in the eighth century. Charles sought to solve it by a characteristic stroke of his truly imperial genius, and though he failed, even the failure attests the grandeur of his conceptions. Near the Bavarian town of Weissenburg a little stream called the Schwäbische Rezat takes its rise, within a few miles of a larger river, the Altmühl. The Rezat flows northward into the Main, and so eventually into the Rhine and the German Ocean. The Altmühl, on the other hand, soon reaches the Danube, and so sends its waters at last into the Black Sea. Charles’s idea (suggested to him by some professed experts, but eagerly embraced) was to make a navigable canal between the Rezat and the Altmühl, and thus transport his troops and their provisions at will by river navigation either northward against the Saxons or eastward against the Avars. During the whole autumn of 793 a vast multitude of men labored at the great enterprise. They dug a fosse two miles long and three hundred feet wide, but it was all in vain. Nature was too strong for them. The marshy quality of the soil, made worse by autumnal rains, thwarted the operations of the diggers, and however much they dug out by day, by night the heaps had all sunk back into the swampy level. There is still, however, a trench about five miles south-west of Weissenburg called the Fossa Carolina, which remains as a monument of the great king’s project. “What a change” (as has been truly said by Pastor Meier, a Bavarian priest who traced the course of the Roman _Limes Imperii_ through these regions), “what stir, and what activity would have filled all those quiet plains if the grand scheme of Kaiser Karl (not yet Kaiser) had been realized, and this tiny streamlet, the Rezat, had seen the interchange of the products of the east and west.” The scheme itself, or something like it, was carried into execution by King Louis I. of Bavaria, but owing to the introduction of the railway system König-Ludwigs-Kanal, like so many other artificial waterways, has lost much of its importance.