W & A K Johnstons' 1906 book explains that this tartan was designed and manufactured in 1890 by Baillie Donald Macmillan, J.P. of Partick, a representataive of the Loch Arkaig branch of the clan, and Chieftain of the Clan Macmillan Society. Patented and registered as Breacanseilgmhicgillemhaoil 'it has already attained great popularity, almost completely supplanting the old clan tartan.' Apparently the former President of the Clan MacMillan Society, Major Cameron Macmillan, always referred to this as Baillie Macmillan's tartan. Cameron was a boy in the 1890s when this tartan was a new product issuing from the Baillie's highland outfitting establishment in Partick. It's said that it did not really catch on until the late Chief, General Sir Gordon MacMillan, decided to dress all his family in it to make them easily identifiable from the rest of the clan who wore the Ancient version.