The tale of the unknown Corsican soldier who rose from nothing to the throne of France, and conquered Europe from the Pyrenees to the gates of Moscow, only to lose it all, is an epic of such drama that, in over two hundred years, only one person has managed to make it boring. Heaven knows how Ridley Scott managed it. Andrew Roberts does a much better job with this new book, which rattles along like a gun carriage charging into action. It is of course a familiar story, not least to Roberts himself. In 2014 he wrote Napoleon the Great, which made the case for bracketing his subject with Alexander, Peter and Frederick. That was a full biography which portrayed Napoleon in action, both on the battlefield and in the council chamber as a civilian lawgiver. It showed his genius in full context, the only way to make proper sense of his whole tragic arc, through hubris to eventual nemesis.

Napoleon and his Marshals returns to this monumental tale. The twist this time is that while of course Napoleon remains in the spotlight, he now shares the stage with the twenty-six men whom he installed as marshals of France. These were the most senior generals in the French army, the men who had helped him rise and who sustained him in his glory. It was a group that reflected the changes wrought by the Revolution. Before 1789, only aristocrats could reach senior ranks in the army of the king. Now, a mere six of the twenty-six came from noble backgrounds. Among the others were the sons of stonemasons, tenant farmers, coopers and innkeepers. Eleven had risen from the rank of private. Some, like Murat, Marmont and Berthier, had been at Napoleon’s side almost from the beginning of his meteoric rise. Others had proved their talent and loyalty along the way.

For twenty years, these men marched and fought, plundered and shagged their way across Europe. All were young: the average age on appointment was only thirty-nine. All were men of war, soldiers with the courage, wit and luck to survive the lethal politics of the Revolution as well as the bloodiest battles of the age. Almost all had been wounded in action at least once. Nicolas Oudinot held the record with thirty-two times. These were men of strong character: tough, competitive and ruthless. They were fast on their feet and with their fists, and they bubbled with self-belief. Their thirst for glory was rivalled only by their greed for money and lust for other men’s wives. Pride and passion led to fiery relationships. Deep hatreds and contempt came between them at least as often as friendships and professional respect bound them together. Napoleon showered them with titles, honours and cash but also played them off against each other in a deliberate game of divide and rule. One minute he flattered, the next chastised, never leaving any doubt about who was in charge.

One drawback of this approach was that many of the marshals never developed the capacity for independent command that became increasingly necessary as Napoleonic armies expanded into the hundreds of thousands of men under arms. Some of the marshals did well on their own, but most never progressed beyond acting as effective subordinates under Napoleon’s supervision. Another, eventually fatal, disadvantage was that Napoleon made unnecessary enemies of them. By 1814 he had treated pretty much every one of the marshals with sufficient contempt to undermine their loyalty. Eventually, when Paris fell to the Allied armies, they turned on him, refusing to fight on and dooming him to exile on the island of Elba. When he escaped and began the campaign that led to Waterloo, only six of the surviving marshals rallied to his tricolour.

No doubt by 1814 many of the marshals were as tired of Napoleon’s jibes as they were of war, and that contributed to their mutiny. Rational calculation of the odds against military success also played a part. Perhaps, however, the marshals’ decision also reflects the weakness upon which the whole Napoleonic edifice was built and which ended up destroying it. The French empire was like a giant Ponzi scheme, every day desperate to find new losers to steal from in order to pay off yesterday’s debts. As long as Napoleon kept fighting and winning, and the bubble kept inflating, the promise of greater gloire and loot kept men like the marshals motivated. When the process went into reverse after the disastrous retreat from Moscow, however, it rapidly spiralled downward.

Napoleon was not the first bling-obsessed national leader to treat his closest aides and allies with contempt, and he was demonstrably not the last. But Roberts is not in the facile comparison game. He judges Napoleon on his own terms, as a man of his time, not ours. Working largely from Napoleon’s own correspondence, and from ground knowledge of the battlefields he fought upon, he has crafted a lively work of unashamed military history. Roberts knows that the only way to understand Napoleon, and especially his relationships with his marshals, is to study them at war. First and last, these men were soldiers, defined by, and embodying, war in all the new horror unleashed by the whirlwind of the Revolution. Roberts gets the level of military detail just right, giving us enough to understand what happened without overwhelming us with minutiae. Excellent maps help, as does an eye for detail. The Napoleonic era forms one of the most vibrant of history’s pageants, and as the colourful parade passes us by, Roberts proves an engaging Dimbleby in our ear, highlighting the features that we must not miss, and occasionally tossing in diverting titbits. I never knew that El Cid’s skull had been stolen, for instance. Now I know the identity of the thief.

The history teacher at Milbourne Lodge, Mr Worton, filled my schoolboy head with the heroics of hussars and Napoleon’s marshals and thereby did more than anyone to inspire me to become a historian. He would have loved Napoleon and his Marshals. There is no higher praise. If, like me, you still thrill to such stories, you will enjoy it too.