When we consider the Middle Ages, we tend to think of France as being one of western Europe’s great powerhouse kingdoms. But it wasn’t always this way: up until the early twelfth century, France was really only a loose collection of counties and duchies whose rulers owed nominal overlordship to a king who exercised direct control over a small royal domain centred on Paris.

This started to change during the reign of Louis VI (1108–37), an authoritative king who in 1124 was able to fight off the threat of a dangerous two-pronged invasion led by Henry I of England on one side and Henry’s son-in-law Emperor Henry V on the other. It was Louis who brought together all of his disparate vassals, appealing to a nascent sense of national identity as he called for ‘all of France’ to follow him. His vassals responded as enthusiastically as he could have wished, and the army that assembled ready to repel the Anglo-German invasion was not merely Louis and a disparate group of lords who recognised him as first among equals; it was a united kingdom of France rallying behind its sovereign.

Louis’s son and successor, Louis VII (1137–80), consolidated his father’s gains. This Louis is best known in England merely as the first husband of Eleanor of Aquitaine, and his reputation has suffered as a result of that failed marriage, but in fact he was an effective ruler. Although not as warlike as his father, he was an astute politician who laid the groundwork for the king who was really going to improve France’s fortunes: his son, Philip II, known as Philip Augustus.

Philip was crowned in 1179, during Louis VII’s lifetime (as was the custom in France). He was just fourteen years old at the time, and he actually had to take the reins of government into his own hands straight away due to Louis’s poor health, becoming sole king upon Louis’s death less than a year later. This meant that the ruler of France was a mere boy, surrounded by enemies both internal and external, all of whom started licking their lips. But Philip had his father’s political acumen and his grandfather’s martial skill and energy, and he immediately set about subduing rebellious vassals and preparing himself for the struggle against the greatest enemy of all.

This adversary was Philip’s opposite number on the throne of England: Henry II, an imposing and daunting figure who, thanks to his holdings in Normandy, Anjou and Aquitaine, actually ruled more of France than Philip did. Henry was vastly more experienced than Philip, having worn the English crown for more than a quarter of a century, and he had four sons – three of whom were older than Philip – to train for future leadership.

Philip wasn’t intimidated, and he recognised that the best way to start undermining Henry’s power was to use those very sons against him. Philip courted them one after the other, and would outwit the whole family by various methods, identifying their individual weaknesses and using them to best effect – Henry II’s insecurity about the loyalty of his children, Young Henry’s fecklessness and lack of acumen, Richard’s single-minded devotion to war, to the exclusion of everything else including politics and good sense, Geoffrey’s duplicity, and John’s ineptitude and the precarious nature of his claim to the throne.
It worked. 

Henry II died a broken man, his sons rebelling against him and in alliance with Philip. Henry the Young King perished while in revolt against his father, with Philip’s support. Richard was killed during a pointless minor siege, his Poitevin barons defying him and Philip’s hand evident in their insurrection. Geoffrey died young, having quarrelled with his father and all his brothers at Philip’s instigation, and leaving his wife pregnant with an heir who would cause the family to fall into further murderous conflict later on, again encouraged by Philip. And John breathed his last as a deposed fugitive in his own land, with Philip’s son and heir halfway to taking his throne and England in total chaos. 

A contemporary writer, seeing all this play out in real time, portrayed Philip as a Capetian falcon swooping down to attack helpless Plantagenet ducks, and he wasn’t far off the mark: by the time Philip died in 1223 the English royal family had been all but annihilated, and the extent of the lands over which the French king ruled was vastly enlarged.

Map of lands ruled by Philip Augustus at the beginning (left) and end (right) of his reign

The history of France would be very different without Philip’s contribution to it. He inherited a small kingdom that was in a precarious position, with over-mighty vassals jostling for power and the looming threat of Henry II and his family casting a forbidding shadow. Philip not only survived this, but thrived and improved his position with every year that passed, demonstrating an immense talent for politics as well as no small degree of martial skill. 

But it’s also true to say that the history of England would have been very different without him. How much longer might Henry II have lived, if Philip hadn’t encouraged his sons to rebel against him, forcing the English king to remain in the saddle without rest or respite for years on end? How much more might the Plantagenet sons have achieved, if Philip hadn’t set them all against each other? His constant ploy of knowing exactly which sore spot to press, which aspect of each Plantagenet’s psyche to attack, was astonishingly successful. The suspicions of Henry II against his sons and the jealousies of those sons among themselves were all fruitfully exploited, to their detriment. There is even a case to be made that if John had lived a little longer – rather than dying and leaving as his heir an innocent child – the crown of England itself might have fallen into Capetian hands, and the destruction of the house of Plantagenet would have been complete.

In the traditional historical narrative, Philip has suffered in comparison with the glamorous and attention-hogging family of Henry II. He’s been characterised partly as a Machiavellian schemer but also as a non-military, almost cowardly man; a mere background antagonist who was lucky that the Plantagenets fought against themselves so often. But few medieval kings were as successful as Philip, and his collection of epithets tells us something about how he was perceived and appreciated during and after his lifetime: Philip the God-Given, Philip Augustus, Philip the Magnanimous, Philip the Conqueror. Unlike many contemporaries he died peacefully in his bed, his enlarged kingdom firmly under his control, his vassals compliant, his enemies cold in their graves and his family succession secure in the hands of a trusted son and grandson (the future Louis VIII and St Louis IX), who were both at his side. His legacy was to leave England in dire straits and France pre-eminent.

You can read more in Nemesis: Medieval England's Greatest Enemy

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