The first phase resulted from agricultural improvement, driven by the need for landlords to increase their income – many had substantial debts, with actual or potential bankruptcy being a large part of the story of the clearances.

The growing cities of the Industrial Revolution presented an increased demand for food;[c] land came to be seen as an asset to meet this need, and as a source of profit, rather than a means of support for its resident population.

The growth in the trade in cattle demonstrates the ability of pre-clearance Highland society to adapt to and exploit market opportunities—making clear that this was not an immutable social system.

The Statutes of Iona controlled some key aspects; this forced the heirs of the wealthier Highlanders to be educated in the Lowlands and required clan chiefs to appear annually in front of the Privy Council in Edinburgh.

[2]: 37-46 The various intervals of warfare since the Statutes of Iona reined in the steady transition to landlordism because the ability to raise a band of fighting men at short notice became important again.

Devine repeats the views of Marianne McLean, that those of them who emigrated were not refusing to participate in a commercial economy; rather they rejected the loss of status that the changes of improvement gave them.

The common drivers of clearance are as follows: Replacement of the old-style peasant farming with a small number of well-capitalised sheep farmers allowed land to be let at much higher rents.

[16]: 175 In the second phase of the clearances, when population reduction was the primary intention, the actions of landlords can be viewed as the crudest type of social engineering with a very limited understanding of the likely consequences.

This, combined with the reduction of duty on the foreign import, and the discovery that cheaper alkali could be extracted from common salt, destroyed the seasonal employment of an estimated 25 to 40 thousand crofters.

Not only did the level of poverty increase in the general population, but many landlords, failing to make prompt adjustments to their catastrophic fall in income, descended into debt and bankruptcy.

[15]: 36–37  Even accepting the level of debate on the subject among historians and the incomplete body of evidence, there is a clear case that, for example, pre-clearance Strathnaver (in Sutherland) experienced recurrent famine in a society operating at the margin of subsistence.

The new Highland landowner class (who had bought financially failing estates) and the remaining wealthier hereditary landlords had the funds to support emigration of their destitute tenants.

The threat of full application, and possible reform, of the Poor Laws (that would have had the effect of formalising the obligation to feed all the destitute in each parish) was the final impetus to the various assisted emigration measures.

James Hunter quotes a contemporary Lowland newspaper: 'Ethnologically the Celtic race is an inferior one and, attempt to disguise it as we may, there is ... no getting rid of the great cosmical fact that it is destined to give way ... before the higher capabilities of the Anglo-Saxon.'

However, religious discrimination is not considered, by some historians, to be a reason for evicting tenants as part of any clearance, and is seen more as a source of voluntary emigration by writers such as Eric Richards.

It was put into effect in a highly organised manner, gathering all the sheep in the area (except that of Donald Macleod of Geanies, the Sheriff Depute of Ross - perhaps out of either fear or respect for him).

[26]: xiii  On 4 September 1785, at the age of 20, Lady Sutherland married George Granville Leveson-Gower, Viscount Trentham, who was known as Earl Gower from 1786 until he succeeded to his father's title of Marquess of Stafford in 1803.

[k][15]: 52-70 Young had a proven track record of agricultural improvement in Moray and Sellar was a lawyer educated at Edinburgh University; both were fully versed in the modern ideas of Adam Smith.

The whole process was a severe shock to Lady Sutherland and her advisers, who were, in the words of historian Eric Richards, "genuinely astonished at this response to plans which they regarded as wise and benevolent".

James Loch, the Stafford estate commissioner was now taking a greater interest in the Northern part of his employer's holdings; he thought Young's financial management was incompetent, and Sellar's actions among the people deeply concerning.

The Transatlantic Emigration Society provided a focus for resistance to the clearances planned in 1820, holding large meetings and conducting extensive correspondence with newspapers about the situation of Sutherland tenants.

Loch worried that this would spread to the Sutherland tenants, but no violent physical resistance occurred, with those cleared demonstrating (in the words of Eric Richards) "sullen acquiescence".

[1]: 224 The flamboyant Alexander Ranaldson MacDonell of Glengarry portrayed himself as the last genuine specimen of the true Highland chief while his tenants (almost all Catholic) were subjected to a relentless process of eviction.

[28] He abandoned his disbanded regiment; its Catholic chaplain (later bishop), Alexander Macdonell led the men and their families to settle in Glengarry County, eastern Ontario, Canada.

[11]: 375  Even before the Crofters' War of the 1880s, Gaelic communities had staved off or even averted removals by accosting law enforcement officials and destroying eviction notices, such as in Coigach, Ross-shire, 1852–3.

[35] Richards describes three attempts at large-scale resistance before the Crofters' War: the Year of the Sheep, protests against Patrick Sellar's clearance of Strathnaver in 1812–4, and the "Dudgeonite agitation" in Easter Ross in 1819–20, sparked by a local tacksman's organization of an emigration fund.

The subject was largely ignored by academic historians until the publication of a best-selling history book by John Prebble in 1963 attracted worldwide attention to his view that Highlanders had been forced into tragic exile by their former chieftains turned brutal landlords.

[citation needed] On 23 July 2007, the Scottish First Minister Alex Salmond unveiled a three-metre-high (10-foot) bronze Exiles statue, by Gerald Laing, in Helmsdale, Sutherland, which commemorates the people who were cleared from the area by landowners and left their homeland to begin new lives overseas.

The statue, which depicts a family leaving their home, stands at the mouth of the Strath of Kildonan and was funded by Dennis Macleod, a Scottish-Canadian mining millionaire who also attended the ceremony.

[50] The diaspora was worldwide, but emigrants settled in close communities on Prince Edward Island, New Brunswick, Nova Scotia (Antigonish and Pictou counties and later in Cape Breton), the Glengarry and Kingston areas of Ontario and the Carolinas of the American colonies.