He led them to Upper Canada, where they received a grant of land in return for their military service in what became the very prosperous Canadian Gaelic-speaking pioneer settlement of Glengarry County, Ontario.

By his energy and perseverance he induced a considerable immigration of Gaels to the province, and left at his death forty-eight churches attended by thirty priests, plus a major seminary and a college.

For example, at the burn known as Allt a bhodaich in Glen Cannich, Màiri ni'n Ailein, the future Bishop's aunt, was struck by the sabre of a redcoat while trying to remove the chasuble of Fr John Farquharson following the latter's arrest in a local Mass house.

Returning to his native land he exercised a secret apostolate for five years in Lochaber,[3] where he was termed in Scottish Gaelic as Sandaidh Mòr ("Big Sandy") and Maighstir Alisdair ("Father Alistair").

Clan chief Alexander Ranaldson Macdonell and John Fletcher of Dunans went to London and presented the documents to King George III, along with letters of commendation from Glasgow merchants.

"They everywhere won golden opinions by their humane behavior towards the vanquished, which was in striking contrast with the floggings, burnings, and hangings which formed the daily occupation of the rest of the military.

Such timely exhortations had almost magical effect, though the terror-stricken population could scarcely believe their eyes when they beheld a regiment of Roman Catholics, speaking their language, and among them a soggarth, a priest, assuring them of immunity from a government immemorially associated with every species of wrong and oppression.

With all the obstacles placed in his way, Bernard Kelly says, "he may be literally said 'to have smuggled his friends away'"[8] Macdonell arrived at York, Upper Canada (now Toronto), 1 November 1804, and proceeded to settle the people on the lands granted by the British government.

[4] Following an 1814 visit to the settlement, Dr. D. MacPherson wrote, "You might travel over the whole of the County and by far the greater part of Stormont, without hearing anything spoken except the good Gaelic.

"[9] Dr. MacPherson continued, "The chief object of my visit to Glengarry was to see an old acquaintance, Mr. Alexander MacDonald (sic), a priest, who has been resident in this country ten years.

Were he ambitious of enriching himself, he might ere now be possessed of immense property; but this appears not to be his object; his whole attention is devoted to the good of the settlement; and the great and numerous services which he has done, cannot well be calculated.

Six years later, 14 February 1826, the vicariate was raised to a bishopric by Pope Leo XII, and Macdonell then became the first bishop of Upper Canada with his see at Kingston.

Macdonell's thorough knowledge of the country and its people and his great administrative ability made his counsel desirable to the government, and on 12 October 1831, he was called to the Legislative Council of Upper Canada, and thereafter was accorded the title "Honourable".

He founded churches and schools and in 1839 established Regiopolis College, which offered academic and theological training to Roman Catholic youth.

[13] Macdonell died from pneumonia on 14 January 1840, aged 77 in Dumfries, Scotland, where he had gone with the hope of interesting Irish and Scotch bishops in a plan of emigration and to raise funds for the college.

He was buried in the crypt of St. Margaret's Convent chapel, Edinburgh, but his remains were subsequently removed to Canada and interred in Kingston Cathedral 26 September 1861.