As General de Gaulle set out for the Middle East in April of 1941, he famously wrote that “towards the complicated Orient, I flew with simple ideas”. They all did. Napoleon was going to “liberate” Cairo, and Bush and Blair were going to “liberate” Iraq; and Obama, briefly, was going to “liberate” Syria.

A magnificent book by the French Saint Cyr Military School historian Henri de Wailly, Invasion Syria 1941, has just been published for the first time in English – and at what a moment. As Stalingrad-size casualties mount in civil war Syria today, here is the story of how the French – and the British — thought they could create “modern” Lebanon and Syria by driving across the border from what was then Palestine and taking over the Levant from the 35,000 demoralised Vichy troops who had been forced since the summer of 1940 to serve Marshal Petain’s pro-German collaborationist regime.

It turned out rather differently, but some things never change in the eyes of the Westerner. Here, for example, is Vichy General Tony Albord on the local Alawite and Lebanese soldiers he commanded – the Alawites, of course, being the same Shia sect to which today’s President Bashar al-Assad of Syria belongs. “The Alawite soldier is capable,” Albord wrote, “the Syrian simple and disciplined, but anti-authority, easily upset and uncultured. His martial spirit is reduced. The Lebanese are conscientious mercenaries, civilians dressed in military uniform. The Lebanese and Syrian middle classes have no esteem for the army; their sons must be lawyers.”

And so they still must be. But back in 1941, things went badly wrong for de Gaulle’s tiny Free French army. The “Army of the Levant” – officially fighting for Vichy France – did not surrender. Anxious to avoid the shame of the French military collapse before the Nazi Wehrmacht in April and May of 1940, it fought with great bravery against both de Gaulle’s rag-tag army and the British and Australians who accompanied them.

The Australians and the Vichy soldiers both hated de Gaulle’s men, and the British also distrusted the Free French. Almost the entire Vichy force – invited to join de Gaulle’s forces to save “the honour of France” – chose to be repatriated to their half-occupied country, many of them in a ship displaying a large banner upon which was written “Vive Petain”.

For the first time, we have this sorry tale written not just from British but from Vichy French archives, wherein we learn that out of 37,000 men fighting for Vichy, 32,380 chose to return to Petainist France, just 5,848 joining the Free French – but 66 per cent of them were African troops who had no interest in the European war. And among the Frenchmen to join de Gaulle, “many were married to Lebanese Christian women and had created families locally that they could not abandon.” Astonishingly, more than a hundred Free French deserted de Gaulle and were smuggled home to France – half of which was occupied by the Nazis – along with their Vichy comrades.

And here, a remarkable coincidence. As I was reading de Wailly’s book, I took a call from British artist Tom Young – the same painter whose efforts to save Beirut’s Ottoman “Pink House” were recorded in this column two months ago – who told me that he’s now trying to preserve the magnificent 1873 Boustani House in a Christian suburb of Beirut. It was built by a Lebanese banker, Salim el-Boustan, whose wife Adele – owner of one of the first pianos in Lebanon (it still survives) – had six children, one of them a beautiful daughter called Georgette.

Back again now to the 1941 Allied invasion of Lebanon. Among the British forces was Sergeant Major Frank Armour, almost certainly fighting in a Scottish Commando unit that was badly hit in the first stages of the attack. He and his fellow officers arrived in “liberated” Beirut and were billeted on the top two floors of Salim Boustani’s home, and last week I walked through their rooms with their beautiful Italian architrave window frames and views over the Mediterranean, a glorious olive garden and banana plantation next door.

But like the French soldiers who married Lebanese women and chose to stay in Lebanon, Frank Armour — whose father was Scots and mother Russian — fell passionately in love with the gorgeous Georgette, married her, and lived on in the Ottoman mansion for the rest of his life. Behind the garden is a Phoenician tomb.

Frank died not long afterwards, the civil war still exploding around the house, Georgette less than a decade ago.

The house was sold to a Kuwaiti and then to a Syrian, Nader Kalai, CEO of the Syrian mobile phone company, Syriatel, and a chum of – you guessed it — Bashar al-Assad.

But you’ve got to be careful in the Middle East. Bashar has accepted Russian military support and may well survive. General Dentz, the Vichy commander in Lebanon, was forced to allow the German Luftwaffe to refuel at French airfields in Lebanon and Syria — at Aleppo, right beside the airfield that is mortared by Nusrah Front rebels to this day — and to hand over weapons to pro-Nazis in Iraq; he was sentenced to death by de Gaulle’s courts in 1944. A Saint Cyr man and a convinced anti-Nazi, he tried to uphold the “honour of France” but as a soldier, he obeyed Marshal Petain and only de Gaulle saved him from execution. Dentz’s army fought so well against the Allies that its exploits have hitherto been largely expunged from French and British – and Australian — histories of the period.

Dentz did not face the firing squad, but he died a slow death, deliberately brought about by a nation which imprisoned him in dank, freezing cells, dripping with water. On 22 November 1955, he wrote in his diary: “They have taken away my overcoat and scarf…I am writing absolutely numb in mind and body.” December 13: “The walls are running like little waterfalls…the best time is when one goes to bed…and, for a few hours, everything is forgotten.” They were his last words.

Petain shared Dentz’s fate. De Gaulle became president of France. Assad remains president of Syria. Better to be a small soldier, I suppose, like Frank Armour. He, too, came to the complicated Orient. Surely not with simple ideas. I guess he fell in love with the place.