The Legend of Bob Leonard.

When a procession of Norman soldiers escort a group of prisoners through the depths of the forest, they are ambushed by a band of bloodthirsty thugs. The Normans routed and shown no mercy, a captive minstrel manages to trade his life for a song. Composed on the spot, he promises his attackers immortality through the ages. But sometimes legends are born by accident, and history can play a game of Chinese whispers with the truth.