When [king] Richard was captured by the Austrians, it was some time before anyone in England discovered where he was. A minstrel called Blondel searched for his master throughout Europe in vain. Returning home through Austria, however, he learned that in an ancient stronghold near Linz there was a closely guarded prisoner whose identity no one knew. Blondel, suspecting the mysterious captive was his master, went to the castle but was unable to catch a glimpse of the prisoner. He eventually located a tiny barred window, high up on the castle wall, which he thought was the prisoner's cell. Under this window he sang the first couplet of a troubadour's song, the first part of which had been composed by himself and the second by Richard. From the window a voice responded with the second part, and Blondel knew that he had found his master.
[According to legend Blondel found employment at the fortress, gained access to the cell, and was the messenger through whom Richard arranged the raising of his ransom with the English nobility.]