The bridge at Montereau

What, you’ve never heard of Montereau? OK, let me tell the story.

Four years ago, you might recall, there was a spate of commemorations for the six hundredth anniversary of the battle of Agincourt, the most famous English victory over France in the Hundred Years War. Henry V of England destroyed a much larger French army on St Crispin’s day, 25 October, in 1415.

But Agincourt, while a big morale boost for the English, didn’t actually conquer any territory. So two years later, Henry returned to France and began the systematic conquest of Normandy, of which his ancestors had been dukes a couple of centuries earlier.

One reason for the victory against the odds at Agincourt had been the state of division in the French camp. The king, Charles VI, was only intermittently sane, and his government was fought over between rival factions – the Armagnacs (supporters of the Dauphin, or heir apparent, later Charles VII) and the Burgundians (supporters of the Duke of Burgundy, John the Fearless).

Armagnacs and Burgundians were both quite capable of intriguing with the English against their rivals. But by the middle of 1419, with Henry master of Normandy and his army threatening Paris, they decided to sink their differences in an alliance against the foreign enemy. Their leaders agreed to meet for the purpose at Montereau, south-east of Paris.

The bad blood between them, however, was too strong. John the Fearless had been responsible for the assassination of the Armagnac leader, Louis of Orleans, 12 years earlier. Now the Armagnacs had their revenge, and while the Dauphin looked on, duke John was hacked to death on the bridge over the Seine at Montereau, six hundred years ago this week.

The short-term consequences were momentous. John’s son, Phillip the Good, became Duke of Burgundy, and immediately shifted towards a full alliance with the English. The following year, in the treaty of Troyes, he induced Charles VI to disinherit the Dauphin and name Henry V as his heir.

So began the climactic phase of the Hundred Years War, as Henry, who had originally just aimed to safeguard Gascony and regain Normandy, now dreamt of complete conquest – the “dual monarchy” of England and France.

The Burgundians, however, made unreliable allies for the English as well; after the Dauphin’s cause had been revived by Joan of Arc, Phillip the Good switched sides in the treaty of Arras in 1435. Normandy held out for another 15 years, but ultimate French victory was only a matter of time.

For Burgundy, Montereau was the signal to turn away from internal French politics. Instead Phillip and his son, Charles the Bold, concentrated on state-building, trying to convert their lands, which stretched from Burgundy northwards in a loose chain to most of what is now the Netherlands, into a major independent power.

The attempt eventually failed, with the defeat and death of Charles the Bold at the battle of Nancy in 1477. Had it succeeded, it would have radically changed the future shape of Europe, with the presence of a substantial buffer state between France and Germany. In that event, Montereau might now be seen as a major turning point instead of a minor curiosity.

Moral? History is full of contingencies, and the past constrains us in ways that we may only dimly understand. With an unusually jingoistic government now in office in Britain, it’s interesting to reflect on the deep roots of Anglo-French enmity. (Including the fact that it was Boris Johnson’s hero, Winston Churchill, who revived the idea of the dual monarchy – or monarchy+republic, as it would have been – in the dark days of 1940.)

But it’s also a reminder that British isolation is a myth, and that Britain has always been deeply involved, one way or another, in continental politics. The Brexiters may fantasise that their island can tow itself under its own steam out into the middle of the Atlantic, but in fact the British are stuck where they are, more closely connected than ever.