Scottish newspapers have been reporting that medieval Scots who fought in battles like Bannockburn, and Flodden Field would have looked very different to the way they have traditionally been depicted.
Instead of kilts, he said they wore saffron-coloured tunics called "leine croich" and used a range of ingredients to get the boldest possible colours. Historian Fergus Cannan claims that some warriors even dyed the garments with horse urine in order to get the boldest possible colours.
Cannan, who claims he can trace his family roots back to the legendary monarch Robert the Bruce, makes the case for a saffron rather than a tartan army in the forthcoming book Scottish Arms And Armour. He asserts that the Scots armies who fought in the pivotal battles of Bannockburn and Flodden Field would have looked very different to the way they have traditionally been depicted.
Cannan said: "What the Scottish soldiers wore in the country's greatest battles is an area that, up until now, has not been properly studied. We know quite clearly what happened at Bannockburn and Flodden, but visual images of these hugely important episodes are very vague and have been muddled by 19th and 20th interpretations which put a romantic gloss on Scottish history. A lot of historians quite rightly stated that the film Braveheart was not terribly accurate, but what they didn't admit was that they didn't have a clue what would be accurate."
The military history specialist scoured original medieval eye-witness accounts, manuscripts, art, sculptures and tomb effigies to build up a picture of what members of Robert the Bruce's forces would have worn in 1314.
He was keen to debunk both the "Braveheart stereotype" of blue-faced, kilted hordes and the revisionist suggestion that medieval Scots soldiers were almost indistinguishable from their English opponents.
He said: "I believe both of these views are equally wrong. There is no need for this period to be shrouded in mystery as there is a wealth of evidence out there, which appears to have been almost completely ignored and overlooked.
"Forget about the plaid and tartan. What Highlanders did wear when they went into battle throughout the Middle Ages, right up until the end of the 16th century, was what English writers refer to as saffron war shirts, known in Gaelic as leine croich."
Cannan claims there were numerous contemporary references to the distinctive linen tunics which were usually worn with a belt round the middle. "The yellow war shirt is never shown in any film or popular image and yet it is something that all the original writers comment on. Saffron was a rare and expensive item to get hold of back then, so the poorer clansmen would have dyed the linen with things like horse urine, bark and crushed leaves to get the rich yellow colour. Historians of the time say the use of the real spice combined with the yards of material used was a symbol of status and the mark of a chieftain."
The author believes that the leine croich was worn for its practicality and could be used as bedding and well as an elementary form of armour. He said: "It was fairly thick and had so many yards of material that it was probably enough to stop a sword blow. When we hear from English writers of that time that Scots went into battle unprotected or semi-naked they didn't understand that what they wore was a form of armour.
"On top of the leine croich an average clansman would wear a deerskin or cowhide jerkin, which would be waxed or dipped in pitch to make it waterproof. However, a Scots nobleman of that era would have worn a long mail shirt or iron-riveted rings and a helmet."
Angus, Chief of Clan Chattan, recorded in 1572 that the "yellow war shirt" was still venerated by his people as "the badge of the Chieftaines".
However, the Gaelic historian Martin Martin, a native of Skye, wrote that saffron garments had fallen out of use at the end of the 16th century. Cannan claims the dyed garments were equally popular with Gaelic-speaking Irish warriors over the same periods in history.
Dr Clare Downham of Aberdeen University believes that Cannan's analysis fits with her knowledge of Celtic Scotland. She said: "The tartan kilt as we know it today is part of a romantic and more modern imagining of Scotland's past. But it is clear from records dating back to the 11th century that the Gaels were well known for going bare-legged and wearing a sort of form of plaid. The Norwegian king went to the Hebrides in 1098 and adopted the dress of the locals and became known as Magnus Barelegs when he returned home. This distinctive form of dress ethnically distinguished the Gaels at that time."