There are nine historical figures which embody the ideals of chivalry (knightly virtues e.g. courage, justice, mercy, generosity, faith, nobility, hope). Historians call them The Nine Worthies. firstly mentioned in the 14th century by Jean de Longuyon (Voeux du Paon) handpicked and sorted into triads as chivalry champions for the Pagan Law, the Old Law, and the Christian Law. Longuyon’s idea was rapidly spread by literature and art in the Middle Ages and got well-established in that way. The nine worthies he had chosen were:

From Pagan Time

Hector - Alexander the Great - Julius Caesar

From the Old Testament

Joshua - David - Judas Maccabaeus

From Christian Time

King Arthur - Charlemagne - Godfrey of Bouillon

These three group of three (nine) combine all aspects of a perfect warrior. All but not Hector, are conqueror, and most of them are descendants of royal families. From their military campaign they all brought back glory to their nations and were perceived as heroes because of their personal valor. Each displayed outstanding qualities of chivalry and let them become exemplars of knight hood. Because GSBA shows the portrait of Charlemagne on its logo, I’m going to explain a little bit more of his role in the European Middle Ages. Charlemagne's reign is often referred to as the Carolingian Renaissance because of the flowering of scholarship, literature, art and architecture. Most of the surviving works of classical Latin were copied and preserved by Carolingian scholars. The pan-European nature of Charlemagne's influence is indicated by the origins of many of the men who worked for him: Alcuin, an Anglo-Saxon; Theodulf, a Visigoth; Paul the Deacon, a Lombard; and Angilbert and Einhard, Franks. Charlemagne enjoyed an important afterlife in European culture. One of the great medieval literature cycles, the Charlemagne cycle or Matter of France, center around the deeds of Charlemagne’s historical commander of the Breton border, Roland, and the paladins who serve as a counterpart to the knights of the Round Table; their tales were first told in the chansons de geste. Charlemagne himself was accorded sainthood inside the Holy Roman Empire after the 12th Century. It is frequently claimed by genealogists that all people with European ancestry alive today are probably descended from Charlemagne. However, only a small percentage can actually prove descent from him. Charlemagne's marriage and relationship politics and ethics did, however, result in a fairly large number of descendants, all of whom had far better life expectancies than is usually the case for children in that time period. They were married into houses of nobility and as a result of intermarriages many people of noble descent can indeed trace their ancestry back to Charlemagne.
Another interesting note about Charlemagne was that he took a serious effort in his and others scholarship and had learnt to read in his adulthood, although he never quite learnt how to write.