The Clan Gregor held lands in Glenstrae, Glenlochy, Glenlyon, Glengyle, and Glenorchy. They were descended from the ancient Celtic royal family through the hereditary Abbots of Glendochart, a descent which is proclaimed in the motto, 'S Rioghal Mo Dhream translated as Royal is my Race.
Tradition holds that Gregor was the son of Kenneth MacAlpin, however he may have been Griogair, son of Dungal, who is said to have been a co-ruler of Alba, the kingdom north of Central Scotland, between AD 879 and 889. Most modern historians agree that the first certain Chief was Gregor of the Golden Bridles. Gregor's son, Iain Camm (Ian of the One-Eye) succeeded as the second Chief sometime prior to 1390.
Robert the Bruce granted the barony of Loch Awe, which included much of the MacGregor lands, to the Chief of the Campbells. In common with many royal gifts of the time, it was left to the recipient to work out how he would take possession of it. The Campbells harried the MacGregors who were forced to retire deeper into their lands until they were largely restricted to Glenstrae.
In 1589 John Drummond, the Kings forester, was murdered after hanging some MacGregors for poaching. The Chief, Alasdair MacGregor of Glenstrae, took responsibility for the act and was condemned by the Privy Council. King James VI, issued an edict proclaiming the name MacGregor "altogidder abolished," meaning that those who bore the name must renounce it or suffer death.
The Proscriptive Acts of Clan Gregor were enacted on the 3rd of April 1603. This draconian ruling authorized the capture of Alasdair MacGregor of Glenstrae and his leading kinsmen. In the spring of 1604, Alasdair MacGregor of Glenstrae, Chief and Laird of MacGregor was hung with thirty of his warriors against the West End of Saint Giles Kirk where the Tollbooth stood. Today, the "Heart of Midlothian" in Edinburgh marks the spot where the MacGregor Chief was executed.
The names of Clan Gregor were erased from existence. To even claim one of these names openly was to invite an immediate execution. The clanfolk of the Gregorach were ordered to take different names, usually assigned. They were to obey implicitly the new Chief placed over them. It should be noted here that many of the Gregors refused. Of those who refused (and were caught); the men were executed, the women were stripped bare, branded, and whipped through the streets. The women and children were sold into slavery for Britain's new colonies in North America.
Further additions to the proscriptive acts denied the Gregors basic necessities of food, water, shelter, and care for infants and the elderly. The Gregors were denied the Sacraments of Baptism, Holy Communion, marriage, and last rites. The gentry of Scotland were encouraged to hunt the Gregors with dogs as if they were common game stock. But, without a doubt, the most horrifying act was the commission of selling Gregor heads to the government to attain pardon for thievery and murder.
The surviving MacGregors continued in two groups. The first were those who legally changed their name to satisfy the law, but never changed their heart or blood. The other group were those who took to the great highlands and continued to use their Gregor names in defiance.
At Loch Katrine on the 7th of March 1671, the 3rd son of Chieftain Donald (Glas) Gregor of Glengyle and Margaret Campbell, cousin to John Iain (Glas) Campbell 11th Laird of Glenorchy, later in 1681 The Earl of Breadalbane, was born and baptised at Buchanan Parish as Robert MacGregor. Because of the proscription he was forced to assume his mothers name of Campbell. His somewhat fictionalized adventures have been immortalized in Sir Walter Scotts novel, Rob Roy.
The persecution of Clan Gregor finally ended in 1774 when the proscription against them was repealed - 171 years later.