King Alfred burned the cakes, right? Wrong. For a start they were loaves – and for another thing, the Vikings reckon their terrifying-sounding hero Ragnar Hairybreeks should take the blame for this ninth century catering disaster.

University of Leeds professor Rory McTurk says the tale of Alfred and the cakes is probably the one story we all know about the Anglo-Saxon ruler, a detail as closely woven into popular history as Robert the Bruce being inspired by a spider and King Harold getting an arrow in the eye.

But he insists it may be mere propaganda, from a time when much of Britain was under Viking control – the Danelaw – and when both sides used stories to bolster their own position and blacken the names of their enemies.

Prof McTurk, of the University's School of English, says the story was used to mark a watershed in the conflict. "Alfred had suffered a series of defeats by the Viking armies – and was virtually in flight at the time," he said.

"The story says he took refuge in Athelney, Somerset, where a swineherd's wife left him to watch the loaves cooking beside the fire. But Alfred was distracted by thinking hard about his fate and about how to fight back – and the loaves burned. The woman reproved him, not realising he was the King."

The English used the story to mark a turning point in his life. "Whether or not the legend is true, Athelney was of massive significance to Alfred," explained Prof McTurk. "He built a fort, rallied his troops and from this point onwards did much better against the Vikings."

But the Vikings had their own stories, tales passed down by the invaders to justify their reasons for being in England. "The hero of one of their stories, Ragnar Hairybreeks, burned loaves too," he said, adding that the change from "loaves" to "cakes" in the story is a much more recent development.

"The English stories portray the Vikings as devils," said Prof McTurk. "The slaying of King Aella of Northumbria in York in 867 is an example – the Vikings carving an eagle into Aella's back, and ripping out his lungs in a horrific sacrifice. But the Viking tradition re-tells the story as a justified act of revenge."

Over the 200 years that followed, the Viking settlers gradually assimilated into the population, but even after the Norman conquest they maintained contact with Iceland, the Orkneys and mainland Scandinavia. And the pro-Viking stories of the Danelaw period were re-told in the Icelandic sagas.

"In the sagas from the 13th century onwards there is quite a lot of information about raids against the English," said Prof McTurk, adding that the intervening years, during which the stories were passed down by word of mouth, had allowed them to change, become distorted – and the propaganda to become "fact".

Which is why we will never know for sure if Alfred the Great – or even Ragnar Hairybreeks – should have passed into legend as the most notorious baker of Anglo-Saxon times.

Professor Rory McTurk's inaugural lecture "Who says King Alfred burned the cakes?" will be given at the University's Rupert Beckett lecture theatre at 5.30pm on Monday March 12. Admission is free, and the lecture is open to all.

Source: University of Leeds.