[13] King Robert the Bruce granted a charter of many lands to Aonghus Óg of Islay, including half the Lordship of Lochaber.

[6][10] According to Angus and Archibald MacDonald, the family seanachie MacVuirich recorded a death account of Alexander "of the Woods", who is referred to as "a powerful, bold, warlike Lord of the Clanranald", who died on the Isle of Abbas in 1460; However, due to the contemporary records being referenced by the Crown holding unto their lands, there is no mention of his territorial magnate.

[6] Traditional rights of the chiefs were being replaced with feudal relationships in which the Crown was the ultimate superior, as part of the royal policy to pacify the Scottish Highlands, including taking charters from lands formerly held by the Lords of the Isles.

[23] In 1501, Alexander Ranaldson was summoned for occupying Morar lands without a title, while the Earl of Huntly's son was granted part of Glengarry.

After James's death at Battle of Flodden, Ranaldson backed Donald Gallda’s claim as Lord of the Isles, leading to clashes with Clan Grant and the invasion of Urquhart Castle.

[6] Angus MacAlester, 7th of Glengarry, used his father-in-law, the chief of Clan Grant, to secure a charter from James VI of Scotland, reclaiming his ancestral lands in 1574.

In response, the Council acquired Kenneth Mackenzie a commission of "fire and sword", and procured through the interest of the 1st Earl of Dunfermline by invading Glengarry's lands of Morar.

While Kenneth Mackenzie sought support from Hector Og MacLean of Duart in Mull, Angus MacDonell raided Lochcarron.

In the aftermath, The Keppoch bard John MacDonald, known as Iain Lom, immortalized the battle in verse, taunting the defeated Campbells to retrieve their lost bonnets from the River Lochy and advising them to "take swimming lessons before returning to Glengarry".

After Donald MacAngus's death in 1645, Aeneas continued serving the King, fighting in Confederate Ireland in 1647 with the army of Thomas Preston, 1st Viscount Tara.

The clan continued as MacDonald until the patent of nobility was granted to Aeneas, who was raised to the Scottish peerage by the title of Lord MacDonell and Aros.

This is stated to be the origin of the name of MacDonell, McDonell or McDonnell, the orthography varying according to the usage of different families descended from the Glengarry branch.

After a year-long spree of cattle raids, robbing inhabitants, and opposing Campbell's authority, Argyll made a complaint to the Privy Council against Lord MacDonell, Lochiel, the MacLeans, and more than 20 defenders for their incursions.

When James II & VII was expelled in the Glorious Revolution of 1688, Alastair Dubh MacDonell, acted on behalf of his father as chief and leader of the Glengarry clan during the 1689 Jacobite rising.

During this time, the MacDonells of Glengarry, along with the MacDonalds of Glencoe began looting and raiding other neighboring clans, including the lands of Robert Campbell of Glenlyon.

In his subsequent appeal for compensation, Robert Campbell of Glenlyon believed the Glengarry men to be the more culpable, making no mention of Glencoe.

John Dalrymple, 1st Earl of Stair's letter to Campbell of Breadalbane on 2 December showed the decision to make an example of Glengarry was taken before the deadline for the oath, originally as a much bigger operation; "...the clan Donell must be rooted out and Lochiel.

Ranald died in 1705 and was succeeded by his son, Alastair Dubh MacDonell, 1st of Titular, Lord MacDonald, and 11th of Glengarry, known as "one of the most distinguished warriors of his day in the Highlands."

[50] Alastair Dubh died at Invergarry in 1721, and was eulogized in the song-poem Alistair à Gleanna Garadh by his kinswoman Sìleas na Ceapaich, which hearkens back to the mythological poetry attributed to Amergin Glúingel and which remains an iconic and oft imitated work of Scottish Gaelic literature.

[52] He was replaced by his kinsman, Donald MacDonnell of Lochgarry, who lead the Glengarry regiment at the Battle of Culloden in April 1746, under the command of James Drummond, 3rd Duke of Perth.

[55] Aeneas's elder brother Alastair Ruadh, later 13th of Glengarry, was captured in November 1745 by a Royal Navy frigate while traveling from France to join in the Jacobite Rising.

Father MacDonell accompanied his clansmen to Glengarry County, Ontario, where he helped resurrect the regiment for active service in the War of 1812.

Sir James MacDonell, brother of the 14th Chief of Glengarry, fought under Arthur Wellesley, 1st Duke of Wellington, winning glory for the clan at the Battle of Waterloo during the Napoleonic Wars.

This event caught the attention of contemporary publications, "We cannot regard the expatriation of the head of an old Highland family, with its clan associations, its pipe music, and its federal recollections, from the battle of Inverlochy downwards, without some regret and emotion".

[59] The departure marked a significant change for the clan and its longstanding connections to their ancestral lands, evoking a sense of sentimentality and reflection.

[59] The 17th chief of Glengarry, Alexander Ranaldson, also returned from Australia, but later sold his estate to the Marquess of Huntly and emigrated with his sons to New Zealand where he later died in 1862.

[60] However, he was "posthumously" succeeded by his distant relative, Aneas Ranald, 19th of Glengarry through the Scotus branch, thus continuing the chief succession of the clan.

[60][61] Aeneas Ranald Wesdrop, 10th of Titular, 20th chief was educated at Eton College, and entering upon a commercial career, he was latterly connected with New Zealand Midland Railway Company, a well-known oil producer in London and Moscow.

Aeneas was educated at St Paul's School, London, and was for a short time connected with the banking firm of Herries Farquhar & Company.

During World War I, he was given the rank of Major and sent on a British military mission in Tbilisi, making the journey on a 36-hour train from Baku in December 1917.