Scarlet

This is Book II of the King Raven Trilogy by Stephen R. Lawhead. William Scatlocke, better known as Will Scarlet, has lost everything to the Normans. He has heard the tales coming from Wales of the exploits of King Raven (who modern readers know as Robin Hood) and decides to join his band of loyal followers. However, during a bold adventure Will is captured. He is subsequently rescued by his friends. And he has uncovered a plot to overthrow the Norman king William the Red. They rush off to warn William Rufus, hoping he'll be grateful enough to return the land of Elfael to King Raven.