It was (Sir Walter) Scott who, to add “aboriginal” colour to George IV’s “jaunt” to Edinburgh in 1822, invented the cult of the clan tartan … arguably one of his finer works of fiction.
'the tartan mania is not a disease which has grown less virulent over the years'.
‘Originally tartan designs had no (Clan) names and no symbolic meaning …’.
One can see how tartan of an area would historically occur – a person would dye wool using the natural colours of the district. But that district / regional tartan wasn’t named.
So, what happened? ‘In 1842 Queen Victoria and Prince Albert visited Scotland. The young couple fell in love with the country, and tartan, which had been simmering for 20 years since the visit of King George IV, bubbled up again…. The brothers John and Charles Allen, calling themselves Sobieski Stuart, finally published Vestiarium Scoticum, (but which was based on drafts from the late 1820s on) which introduced 75 new tartans to the delight of the trade.’
Consider the Verstiarium Scoticum. The book’s authors presented the text ‘as historical proof of the connections between tartans and family clans, a link that previously had no record. The Stuarts’ claims were later found to be completely false; the tartans in the book were in fact designed by the brothers themselves. Even still, their fabrications are to this day widely accepted as authentic by manufacturers and families alike’.
So, a whole pile of named tartans were created for the Verstiarium Scoticum and given a fictional history so tourists would buy them. And Gunn tartan is in the book. Now there is a chance that this Gunn tartan reflected earlier tartan worn by Gunns and others near them – that chance offers one reason why Mackay, Gunn, MacWilliam and Morrison tartans look so similar. But named Gunn tartan is nothing more than a Victorian invention to get money from historically confused tourists and which continues to do so.
As I have said before so much of Gunn ‘history’ is mythology and named Gunn tartan is part of the mythology.
 http://www.the-tls.co.uk/tls/public/article1039746.ece accessed 15 July 2018.
 p. 167, Michael Brander, The Making of the Highlands, 1980 Constable, London.
 http://scottishtartans.org/downloads/fact_sheet_tartan.pdf accessed 15 July 2017.
 http://www.tartansauthority.com/research/researchers/james-grant/ accessed 15 July 2017.
 http://www.brooklynrail.org/2012/06/art_books/vestiarium-scoticum accessed 16 July 2017.
 https://commons.wikimedia.org/wiki/Category:Tartans_from_the_Vestiarium_Scoticum accessed 16 July 2018. And is described on page 88 of the original book. I note it makes reference to the Gunns as Ghuine which gets back to the original name of the Gunns.