My dungeon did not lie beneath the moat, but was in one of the most high parts of the castle. 

So stout was the door, and so well locked and secured withal, that escape that way was not to be found. 
By hard work I did, after many days, remove one of the bars from the narrow window, and was able to crush my body through the opening; but the distance to the courtyard below was so exceeding great that it was certain death to drop thereto. 

Yet by great good fortune did I find in the corner of the cell a rope that had been there left and lay hid in the great darkness.
But this rope had not length enough, and to drop in safety from the end was nowise possible. 

Then did I remember how the wise man from Ireland did lengthen the blanket that was too short for him by cutting a yard off the bottom of the same and joining it on to the top. 

So I made haste to divide the rope in half and to tie the two parts thereof together again. 
It was then full long, and did reach the ground, and I went down in safety. 

How could this have been?

See answer