There were, in those days, as is well known to German antiquaries, few castles or fortresses of much importance in Germany, which did not communicate by subterraneous passages with the exterior country. In many instances these passages were of surprising extent, first emerging to the light in some secluded spot among rocks or woods, at the distance of two, three, or even four miles. There were cases even in which they were carried below the beds of rivers as broad and deep as the Rhine, the Elbe, or the Danube. Sometimes there were several of such communications on different faces of the fortress; and sometimes each of these branched, at some distance from the building, into separate arms, opening at intervals widely apart. And the uses of such secret communications with the world outside, and beyond a besieging enemy, in a land like Germany, with its prodigious subdivision of independent states and free cities, were far greater than they could have been in any one great continuous principality. In many fortified places these passages had existed from the middle ages. In Klosterheim they had possibly as early an origin: but by this period it is very probable that the gradual accumulation of rubbish, through a course of centuries, would have unfitted them for use, had not the Peasants' War, in the time of Luther's reformation, little more than one hundred years before, given occasion for their use and repair. At that time Klosterheim had stood a siege, which, from the defect of artillery, was at no time formidable in a military sense; but as a blockade, formed suddenly when the citizens were slenderly furnished with provisions, it would certainly have succeeded, and delivered up the vast wealth of the convents as a spoil to the peasantry, had it not been for one in particular of these subterraneous passages, which, opening on the opposite side of the little river Iltiss, in a thick _boccage_, where the enemy had established no posts, furnished the means of introducing a continual supply of fresh provisions, to the great triumph of the garrison, and the utter dismay of the superstitious peasants, who looked upon the mysterious supply as a providential bounty to a consecrated cause. So memorable a benefit had given to this one passage a publicity and an historical importance which made all its circumstances, and amongst those its internal mouth, familiar even to children. But this was evidently _not_ the avenue by which Maximilian had escaped into the forest. For it opened externally on the wrong side of the river, whilst everybody knew that its domestic opening was in one of the chapels of the _schloss_; and another circumstance, equally decisive, was, that a long flight of stairs, by which it descended below the bed of the river, made it impassable to horses.