A little bit on the Campbell of Cawdor tartan:

Oringially it was a military tartan, as the Argyll militia (the forerunners of the modern Argyll & Sutherland Highlanders) were kitted out in it at the turn of the 19th century. Nowawadays it is associated with the Cawdor branch of the Clan Campbell.

Argyll is Campbell country, and the tartan became associated with the Argyle (the old spelling that is on my grandmother's grave in Iowa) or Argyllshire.

Cheers,

Todd