GlenLyon is the name of the historic homeland of the ancient MacDiarmid Clan of Scotland. The race takes its name from Diarmid O'Duibthne, the Fingalian Hero who battled and slew the fierce Wild Boar that terrorized his village. After the Battle of the Boar was fought and won and Diarmid was basking in his glory, a rival for Diarmid's Lady-Love challenged him to measure the hide of the slain Boar with his naked feet. Unfortunately, unknown to our triumphant Hero, the bristles of the Wild Boar were poisonous. As our Hero walked the length of the slain critter to see how long his trophy measured, one of the poisonous bristles pricked Diarmid and he subsequently died a terrible and agonizing death. A good argument for the metric system.

The Wild Boar and the Clasped Belt, emblazoned with the words "Ne Obliviscaris" (Do Not Forget), were on the original Clan Crest.

The War Cry of this ancient Race of Diarmid is "Cruachan!" and the official Pipe Music is "Baile Ionaraora". Whatever that means.

The original race of Diarmid is said to have ended during the reign of Alexander III, when Eva, daughter of the last of the O'Duibthne Clan, married Archibald Campbell and "carried away the possessions of her house". Since that time, a few wars and many marriages have continued to intertwine and convolute the histories of Clan MacDiarmid and Clan Campbell. In most instances, the MacDiarmid Blazon of Arms, Shield, Crest Tartan and Pipe Music are also those of the Campbell Clan.