This is not just the story of an officer in the Duke of Wellington's army: it is the story of a regiment - that particularly British institution which Sir John Keegan, the most percipient historian and observer of all things military, has described as 'an accidental act of genius'. Every regiment was - still is - different and revelled in that difference. The difference was not just in the people but in the regiment's history and traditions - the received notions of how things should be done, the esprit, the spirit.

The 6th Light Dragoons are a fictitious regiment, but the events in which they take part are historical fact. The major characters outside the regiment are real figures of history.

Occasional liberties have been taken - General Slade did not go to Ireland in 1814, for instance - but not in any way that changes the historical plausibility of the story. The army of 1814 was singular. It had endured five years of campaigning in the Peninsula, and it had gone from success to success, until the duke was able to remark, famously, that it 'could go anywhere and do anything'.

Now, on the eve of Bonaparte's defeat, it found itself in a particularly commanding position. At Aboukir in 1798 and Trafalgar in 1805, the Royal Navy had confined Napoleon to Europe; British money had financed the allies when they were ready to rejoin the fight; and a British army in the Iberian peninsula had, from 1809, maintained a front which had drained French resources and given hope to other Europeans - the so-called 'Spanish ulcer'.

Thus it was that by the beginning of 1814 Bonaparte could defend only France: Russian, Prussian and Austrian armies were closing in from the east, while the British, already over the Pyrenees, stood ready from the south-west.

This was the situation facing young Cornet Hervey and his regiment as they stood on the southern doorstep of France: perhaps one more battle, and their fate, and the rest of Europe's, might be settled for their lifetime . . .