On the morning of August 22, 1485, the history of England shifted decisively with the death of Richard III at Bosworth and the victory of his rival, the rebel Henry Tudor.

This was the battle that ended the Middle Ages and ushered in the dynasty of Henry VIII and Elizabeth I, but the exact spot where the kingdom was won and lost has remained a mystery, until now.

Just after midday yesterday, Glenn Foard stood on Ambion Hill in Leicestershire, next to the award-winning Bosworth Battlefield Heritage Centre, pointed at the distant church spire of Stoke Golding and declared an end to 500 years of arguments over the location.

“It’s over there, two miles away,” he said, beyond and below the church, off to the right a bit and spread over 250 acres of what is now flat farmland, crisscrossed by hedgerows, pasture and autumnal trees.

Mr Foard, a battlefield archaeologist who has led a four-year, £1.3 million investigation into the whereabouts of the fighting, funded by the Heritage Lottery Fund and Leicestershire County Council, is convinced that he has unearthed the proof.

In an unexpected and thrilling development for the archaeologists, that proof is in the form of 22 lead cannon and musket balls that dramatically reshape thinking about late medieval combat.

Not that the public are allowed to see any of this for themselves yet, or even know exactly where it is. There are fears that this might alert “night hawks” — treasure hunters armed with metal detectors who have removed vital evidence from other battlefields around the country.

According to Mr Foard, his team has discovered more lead artillery shot at Bosworth than has so far been recovered from all the other 15th-century and 16th-century battlefields in Europe put together. It predates by ten years the earliest hard evidence for cannon used as mobile battlefield weapons, as opposed to on board ships, in garrisons or for long-term sieges.

Abandoned cannonballs and bullets are a gift to battlefield archaeologists because they decay far less quickly than iron and steel handweapons and because, if they are made of lead like the ones at Bosworth, their condition shows what happened to them, from the pressure they were fired under to what they hit when they landed.

The Bosworth discoveries range in size from musket balls up to a 7.2kg cannonball. They are distributed in two clusters and may have been fired by both sides.

According to Steve Walton, a specialist in medieval artillery at Pennsylvania State University, “the standard military history says that artillery becomes mobile when the French invade Italy in 1494-95”.

The finds at Bosworth suggest that similar investigations on the Continent, where the use of military hardware was more advanced, would unearth more evidence that firepower was a significant battlefield weapon much earlier than previously realised.

Mr Foard’s organisation — the Battlefield Trust — English Heritage and the county council hope that it will be possible to open the site up next year once they have agreed with the various landowners who own the battlefield how to protect it from treasure hunters. For now their priority is to make the case for more funding to finance further exploration of the site.

The Bosworth study was the most ambitious undertaken in this country, as befits an encounter regularly cited as one of the four most important battles in English history (along with Hastings, Cromwell’s Civil War victory at Naseby and the Battle of Britain).

Experts from various disciplines reviewed the scant original documentary evidence for the battle, reconstructed the landscape of the area from contemporary accounts, tracked the development of local place names, analysed soils and peat deposits (in the search for the 15th-century marsh that played a crucial tactical role on the day) and finally conducted an intensive archaeological survey of the likely sites using metal detectors.

The credentials of the Ambion Hill site were examined and dismissed along with Peter Foss’s suggestion that it was fought on low-lying ground between the villages of Shenton, Upton, Stoke Golding, and Dadlinton and (much to Leicestershire county council’s relief) Michael K. Jones’s theory that the battle was eight miles away in Warwickshire.

By March 1 this year Mr Foard’s team of volunteer metal detectors had only one likely field left to survey and were no closer to identifying a new location with certainty.

“I was completely disillusioned,” he said. “I stood at that gate to the field and said to the chaps, ‘This is it. Either we find it in this field or we are not going to find it’. About an hour later one of them walked up to me and dropped this artillery lead roundshot into my hand and I knew I had found the Battle of Bosworth.”

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