‘Truth is stranger than fiction’. It’s an often-quoted cliché but one that frequently proves accurate. Real history can be more shocking, surprising, and entertaining than fiction.
Ser Barristan Selmy, the Kingsguard commander who defected to Daenerys, appears to be like an idealised staple character of medieval literature. Selmy was a renowned knight who was an exceptional jouster in his youth; he was a loyal member of the Kingsguard to four kings and a figure who continued to be a force to be reckoned with well into his old age.
Indeed, some cynical readers/viewers may be sceptical of the idea that, after being dismissed by Joffrey on the grounds of old age, Ser Barristan became a distinguished member of Daenerys Targaryen’s ‘Queensguard’ by providing both wise council and demonstrating considerable prowess in combat.
Ser Barristan’s story mirrors the even more exceptional life of William Marshal, 1st Earl of Pembroke (1147-1219) who rose from obscurity to serve four Kings of England, became one of the most powerful men in Europe and was eulogised by Archbishop Stephen Langton as “the best knight that ever lived”.
Born the younger son of a minor Anglo-Norman nobleman, William had few prospects since he would not inherit any of his father’s lands or wealth. Worse, his father, John Marshal, had little regard for William. During The Anarchy (the war of succession between the named successor, Empress Matilda, and the man who beat her to the crown, King Stephen), William’s father declared for Matilda in 1139. In 1152, King Stephen besieged Newbury Castle and held the young William hostage to ensure that John Marshal surrendered. However, upon hearing that his son would either be hanged or catapulted at the castle unless he surrendered, John declared: “I still have the hammer and the anvil with which to forge still more and better sons”. Fortunately, according to William’s biographer, Stephen could not bring himself to harm the young boy.
As his father’s fortunes faltered, William was sent to Normandy to be raised in the household of the great magnate William de Tancarville (a cousin of William’s mother). Following his move to Normandy, William spent a brief spell in Upper Normandy fighting against Flanders. This led to his knighthood in 1166 and his capture in 1168. Upon hearing of his imprisonment, Queen Eleanor of Aquitaine herself ransomed him: she had heard tales of the young knight’s bravery. After his release the young knight sought out his fortune as a tournament fighter. Unlike the jousting contests of later centuries, twelfth-century tournaments were often dangerous and deadly arranged battles in which victors could make a considerable fortune from prizes awarded by the organisers (as well as by capturing and ransoming opponents!). William’s tournament record was legendary: he supposedly unhorsed over 500 knights during his career and is believed to have been the only man ever to have unhorsed Richard, duke of Poitou (who would later become the legendary Richard I ‘The Lionheart’ of England).
By the time of Richard’s revolt against his father, Henry II, in 1189, William had been one of Henry’s most loyal and trusted captains for four years. While covering Henry’s retreat from Le Mans to Chinon, William unhorsed Richard in a skirmish and could have killed the prince but killed his horse instead to prove his point.
Similar to how Barristan Selmy was retained as Lord Commander of the Kingsguard following Robert Baratheon’s victory over the Targaryens, Marshal’s former adversary, the newly-crowned Richard I, welcomed him back to the English Court.The king clearly saw the value of the knight’s legendary military prowess and loyalty to the English crown. These traits were particularly valued by the Lionheart as he departed on the Third Crusade in 1190 and appointed the loyal Marshal to the Council of the Regency in his absence. The King’s faith was clearly rewarded as William took up arms against Prince John, when the King’s brother attempted to launch a rebellion with the assistance of Philip II of France. Once again, the Marshal’s loyalty was greatly rewarded as Richard allowed him to succeed his brother to the hereditary Marshalship of England and he was appointed the custodian of Rouen and the royal treasury during the Interregnum.
Following Richard I’s death on campaign in 1199, William backed Prince John’s claim to the English crown against the supporters of Arthur of Brittany (the teenage son of John’s older brother, Geoffrey) and he was heavily engaged in the defence of Normandy against Philip II’s armies . Following the 1203 loss of Normandy to the French, William paid homage to Philip to to secure his Norman lands within the duchy. This led William and John to argue publicly and be openly hostile to each other for four years. In the following five years, John had the Marshal humiliated at Court and allowed his justiciar in Ireland to raid and pillage William’s lands in Leinster. Nonetheless, even before John took him back into royal favour in 1213, Marshal loyally supported John against his barons (a struggle that led to Magna Carta in 1215). Indeed, William was one of the few earls who sided with John in the First Barons’ War (1215-17) and it was the Marshal who John trusted on his deathbed to ensure his son succeeded as Henry III in 1216.
By 1216 the 69-year old William Marshal was the elder statesman of England — and although he had already lived longer than the vast majority of his contemporaries, his finest hour was yet to come. Following the death of King John, the King’s Council named Marshal as Regent of the Kingdom and Protector of the nine-year old Henry III. In spite of his age, Marshal rigorously pursued the war against the rebel English barons and their French allies under Prince Louis (who the barons had declared King of England following John’s death). The next year, the seventy-year old Marshal personally led the English army against the French army of Thomas, Comte du Perche and won a spectacular victory at the Second Battle of Lincoln. This led to the Treaty of Lambeth, ended the Barons’ War and nullified Louis’s pretensions for the English throne.
Compromise and self-restraint characterized William Marshal’s regency. He attempted to secure peace and stability for the young Henry III by reissuing Magna Carta to show the barons that the Crown intended to honour its promises. The Angevin Royal Dynasty founded by Henry II probably wouldn’t have survived the turbulent rule of King John without the presence and prestige of William Marshal: rebel barons and French noblemen alike trusted his word above that of any King or Royal Official.
In March 1219 William’s health began failing: he died on 14th May at the age of seventy-two. In his lifetime he had risen from obscurity, lived an adventurous life worthy of fiction, become the most powerful man in England and ensured the survival of a royal line which continues to this day. In short, he was the greatest knight who ever lived: the tournament champion, the loyal soldier, the pragmatic politician, the Regent of England, ‘The Marshal’.
 Sidney Painter, William Marshal, Knight-Errant, Baron and Regent of England, (1933), p. 289.
 Paul Meyer, L’Histoire de Guillaume le Maréchal (Paris: Société de l’histoire de France, 1891–1901)