Knight In Shining Armor / Real Life

• William Marshal, 1st Earl of Pembroke, was the younger son of a minor nobleman who became the tournament champion of all Europe and went on to serve the royal family of Henry II of England and be given the hand and estates of Isabel de Clare, eventually rising to become the right hand man of three successive Kings (Henry II, Richard I and John), and regent to a fourth (Henry III), fighting in battle in his 70s. He eventually came to be known by his contemporaries as "The Marshal" and "the greatest knight," getting a real life Historical Hero Upgrade by featuring in a number of chansons de geste. He's also notable as reportedly being the only man ever to defeat Richard the Lionheart in combat.
• Godfrey of Bouillon, first ruler of the Kingdom of Jerusalem^* When the Crusaders decided to elect him as the ruler of Jerusalem, he eschewed the title of King, on the grounds that no one should "wear a crown of gold where his Saviour wore a crown of thorns", preferring Advocatus Sancti Sepulchri (Advocate of the Holy Sepluchure) instead, was a leading crusader in the First Crusade, and unlike his relative Baldwin of Edessa and his contemporary, Bohemond of Taranto, he was a genuinely honest and pious man seeking to execute what he thought was God's will. Like William Marshal, he also underwent considerable Historical Hero Upgrade, ranking next to Charlemange and King Arthur as the third Christian Worthy.
• Zig-Zagged with Edward, the Black Prince. He was scrupulously honourable in the treatment of his noble prisoners, including French King John the Good, even giving John permission to go home at one point, as well as delaying the Battle of Poitiers for a day to allow both sides to discuss the battle and Cardinal Périgord to plead for peace. However, he also favoured the chevauchée strategy, which is essentially short-hand for Rape, Pillage, and Burn for reasons of strategic expediency.
• Geoffroi de Charny, who literally wrote the manual on chivalry was widely regarded in his day as a True and Perfect Knight. His reputation for honesty was such that when captured by the English, he was released on parole to collect his ransom and he found someone to pay it, true to his word. He famously proposed that the Battle of Poitiers in 1356 be settled by a hundred champions from each side to limit loss of life. His proposal was rejected and he died in the battle, defending the sacred Oriflamme banner of France to his last breath.
• Enguerrand VII de Coucy had much the same stature as Charny in the later half of the 14th century. He was given to the English as a hostage to secure the release of King Jean II, who had been captured in the battle of Poitiers, but King Edward III of England was so impressed with his courtesy and character that he allowed him to marry his eldest daughter, Princess Isabel. He later returned all his English lands and titles upon the accession of Richard II. Coucy became the role model for a whole generation of young French knights as an experienced campaigner and paragon of virtue. Finally in 1397, he was wounded and captured in the Battle of Nicopolis against Ottoman Sultan Bayezid I, and died before he could be ransomed.
• Richard I and his Worthy Opponent, Saladin, were both elevated to this status by later popular history, to the point where Saladin became significantly more famous and well regarded in the West than he was in the lands he had once lived.
• Pierre Terrail, seigneur de Bayard, was known in his lifetime as "the knight without fear and beyond reproach" and, to his friends, "the good knight". He served three kings of France with absolute loyalty, unimpeachable courage, chivalry and honor, and exceptional skill in war. Right up until the 20th century the name "Bayard" was a byword for courage and virtue.
• Zawisza the Black was considered to be a model of knightly virtues in Poland in his lifetime and even more after his death. He served two kings, Władysław Jagiełło (of his native Poland) and Sigismund of Luxembourg (the king of Hungary and Holy Roman Emperor). Interestingly, in the Battle of Grunwald, where Sigismund allied with the Teutonic Knights against Poland, he decided that his national identity trumped the commitments to his overlord Sigismund, a sentiment quite innovative in the Middle Ages. Apart from being a jousting champion (in 1421 he defeated Prince John of Aragon at a tourney in the castle of Perpignan), he was also an accomplished diplomat and frequently negotiated peace treaties. He died while fighting Ottoman Turks in Serbia. Even today, in Poland his first name (quite a popular name at the time) is shorthand of chivalry and righteousness.
• John Hunyadi was known as the "White Knight of Wallachia" and much like Godfrey of Bouillon, was also was revered by his contemporaries for his crusade against the Ottoman Empire. His deeds led him to be awarded the title of Athleta Christi (Champion of Christ) by The Pope and he was respected by his enemies, with Sultan Mehmed II allegedly grieving at his death when Hunyadi perished from the plague and that was shortly after Hunyadi dealt him such crushing defeat at the Siege of Belgrade that the Ottomans were unable to advance into Europe for 70 years. Today he is a Hungarian national hero and also revered as an example of chivalry in Serbia, Romania, and Bulgaria.
• Franz von Sickingen was a German knight that cultivated this public image of himself as "protector of the oppressed", often taking the side of the weaker party in many political disputes to the point he eventually earned the favor of the Holy Roman Emperor Maximilian I. This led him to participate in the Protestant Reformation when he granted asylum to Martin Luther which culminated in leading the failed Knight's Revolt in order to stop the decline of the status of the imperial knights.
• Sir Giles d'Argentan was known in the early 14th century as the "third best knight" in all of Christendom. Since he was just an ordinary knight, and the top two were the Holy Roman Emperor and King Robert of Scotland, this ranking was particularly notable. He died at the Battle of Bannockburn, fighting on the English side — having seen that the battle was lost, he escorted King Edward II to safety before telling him: "Sire, your protection was committed to me, but since you are safely on your way, I will bid you farewell for never yet have I fled from a battle, nor will I now." He charged back into battle and died.