Was Charlemagne a Redhead?

I've recently read on a few websites that the Emperor Charlemagne had red hair. So far I haven’t found a source text that confirms this, however whilst reading ‘The Life of Charlemagne’ by the Monk of Saint Gall I came across this odd tale concerning red hair;

“So he [a bishop] mounted the pulpit as though he were going to address the people. All the people ran together…except one poor red-headed fellow, who had his head covered with clouts, because he had no hat, and was foolishly ashamed of his red hair. Then the bishop [said] "Bring me that man in the hat who is standing there near the door of the church." The doorkeeper made haste to obey, seized the poor man and began to drag him towards the bishop. But he feared some heavy penalty for daring to stand in the house of God with covered head, and struggled with all his might to avoid being brought before the tribunal of the terrible judge. But the bishop, looking from his perch, now addressing his vassals and now chiding the poor knave, bawled out and preached as follows: -"Here with him! don't let him slip! Willy-nilly you've got to come." When at last force or fear brought him near, the bishop cried: "Come forward; nay you must come quite close." Then he snatched the head-covering from his captive and cried to the people: -- "Lo and behold all ye people; the boor is red-headed."”

This text was supposedly written in the 9th Century AD. I guess it shows that even in those days red hair was something of a curse.