Following the "Glorious Revolution" which brought William and Mary to the throne in place of the deposed King James VII, the supporters of the quondam King, called Jacobites from the Latin form of the name James, staged the first of three major Jacobite rebellions. Once this first rebellion was crushed, the government embarked on a policy of pacifying the Highlands, using a carrott and stick policy of bribery and favors, on the one hand, and military supression on the other.
In late 1691, the government of King William offered an amnesty to those clans who had participated in the abortive rebellion provided their clan chief were to swear an oath of loyalty to the new King prior to the first of the year (1 January 1692).
Alastair MacIan, the elderly chief of Clan MacIan (a sept of Clan MacDonald), undertook a journey to Inverary in order to take the oath. However, he was delayed en route, and the proper authority was not present upon his arrival. As a result, though he took the oath, he did so a few days late. The missed deadline in taking the oath would be used by government forces as a pretext to make an example of the MacIans so as to keep any other rebellious-minded clans in check.
The actual massacre took place on the morning of February 13, 1692. Government troops, under the command of Robert Campbell had been hospitably billeted among their intended victims for two weeks prior to that, waiting the arrival of additional forces who were supposed to seal off escape routes. In the end, 38 members of the MacIan clan were slaughtered, including the clan chief Alastair MacIan, with a similar number perishing of exposure in the snows as they attempted to flee the scene.
The principal source of information on the Glencoe Massacre is the Report of the Commisssion of Inquiry which was set up by the Scottish Parliament to investiage the matter in 1695 and published in 1703. This report is the basis for all writings on the subject, including the book by popular historian John Prebble (Glencoe, first published by Penguin Books in 1966 and since reprinted many times) which can likewise be recommended.