Over 1,000 years ago, vast armies from what are now Scotland and Ireland swept into a field here to be defeated by soldiers from the emerging nation of England.

No they didn’t, says Michael Livingston, an American historian, who argues that the battle known as Brunanburh happened some 100 miles west, near Liverpool. Mr. Livingston, though, is flat out wrong, says Damo Bullen, a British music festival organizer turned bookseller, who like many others says the battle happened somewhere else entirely.

In Britain, historians love to fight over battle sites, but few elicit such stridence and obsession as Brunanburh. There are more than 30 proposed locations for the battle, which took place in 937, and helped shape what would become England.

Brunanburh’s important historic role, and a dearth of contemporary sources describing where it happened, have led people to war over its location for centuries, making it one of the fiercest battle battles.

Traditionally the realm of bickering academics, the issue has grown more heated as the internet and social media give a platform for amateur archaeologists and have-a-go historians.

Battle recommenced this year when Mr. Livingston, a professor at The Citadel, South Carolina’s military college, released a book pinpointing Brunanburh as happening on the Wirral Peninsula, near Liverpool. Mr. Livingston started delving into Brunanburh over a decade ago and has suffered vitriol for his views ever since, he said, including receiving a death threat.

“I started getting these communications that were strident and extremely angry,” he said. “It was: How dare you Yank, get involved in ‘our history,’ ” he said.

Tensions are clear in polarized online reviews of the book, “Never Greater Slaughter,” where those critical talk of “shoddy research” and a “so-called historian.”

“It’s simple to say that social media and the internet have changed everything, but it’s also simply true,” said Mr. Livingston, who believes the opening up of academic debate is overall a good thing, even if he could do without the nastiness.

His website asks that if people need to contact him: “Please send him a friendly email.”

One non-abusive adversary is Michael Wood. The lauded British historian and TV presenter thinks Mr. Livingston and others arguing for the same battle location are absolutely wrong, and says he’s been subject to hostility from “the Wirral lot” for saying that.