The rain poured down and many of the men sleeping on the battlefield that night were crippled with dysentery. Some were also doubtful about the cause for which they were about to fight, but this month, as we approach the anniversary of the Battle of Agincourt, fought on 25 October 1415, a novel commemorating the English triumph 593 years ago has leapt to the top of the bestsellers’ list after just five days on the market.

Agincourt, by Bernard Cornwell, the creator of fictional Napoleonic soldier Richard Sharpe, is quickly confounding expectations for historical fiction, with one of the country’s largest book chains, Waterstones, reporting unprecedented sales. ‘Bernard’s books are always bestsellers, but we seem to be reaching an even wider readership with this book,’ said Amanda Ridout, managing director of publishing house HarperCollins.

As the author of the successful series of 21 books chronicling the adventures of Sharpe, played on the small screen by Sean Bean, Cornwell has a big fan base. His reputation for meticulously detailing the experiences of soldiers has seen the new novel - the title is the site’s French name - sell 13,000 copies.