When people speak of periods when a massive drop of population occurred in Ireland, attention tends to focus on the 1845-51 period of the Great Famine. However, there have been earlier periods well into the era of historical documentation when proportionately speaking, the loss of people was greater, sometimes much greater.
The 1650s was one such decade. To put it into context, Oliver Cromwell had landed in Dublin in late 1649 and proceeded to subdue the rebellion that had begun in 1641. In the few short months he spent here, numerous towns were stormed and sacked with much slaughter and loss of life. The conflict was to continue into the early 1650s when with a scorched earth policy of destroying crops and foodstuffs and burning homesteads, the last pockets of resistance were finally overcome.
It will seem coldly analytical but I'm interested in the numbers of deaths and what I'll being doing in this thread is looking at different statistics and sources. Various sources quote William Petty who estimates that by 1652, out of a total pre-war population of 1.5 million, 618,000 had died or were killed (1). McManus seems to turn this on its head and says that out of 1.466 million, 616,000 were left alive (2).
Source 3 works with a "lowest projected figure" of 200,000 deaths pointing out that this still represented over 10% of the population. Where things get confusing is on estimates of population in 1700 when a period of calm (albeit resentful) had been imposed. Source 3 gives it as 2 million which seems scarcely believable if the population in 1652 had been roughly 1.26 million, going by the maximum estimates. Bear in mind that even though the rebellion had been largely put down by 1652, the country was still in a state of turmoil. The Act of Settlement (the "To Hell or Connaught" decree) was still to come and whilst we can only surmise, it's reasonable to assume that this would have led to conditions under which the population would have fallen further. McManus cites examples of the conditions of the time and of the people being driven westwards (4) - this in a decade which saw the onset of the Maunder Minimum when winters in Europe were particularly harsh.
The next checkpoint in Irish population figures seems to be in the late 1730s where a figure of 3 million is mooted - this ironically in tandem with another (climatic rather than human-made) disaster which led to the deaths of some 400,000 people or roughly 13% of the population (6).
All in all, Petty's absolute figures probably underestimate the total population at the time. Other researchers have since made the point that he based his figures on the Hearth Tax even though many households tended to be missed by collectors (5). One researcher (7) radically upgraded Petty's estimates by two-thirds and arrived a population of 3 million as early as 1725. Other researchers have tended towards the belief that Petty's figures aren't so wildly inaccurate (8). But to reach a population of some 3 million by the mid-18th century would have required a much higher base of population in the 1660s than Petty would appear to be suggesting.
However, the number of deaths up to 1652 may well be pretty accurate given that Petty was subtracting one underestimated figure from another which we can only assume was roughly equally underestimated. If he was out by one million or so, that still leaves a death rate that, in percentage terms, is well in excess of that that occurred during the famine of the 1840s - and that doesn't include deaths post 1652 during the implementation of the Act of Settlement.
1. p. 214 Going to the Wars: The Experience of the British Civil Wars, 1638-1651, By Charles Carlton (viewable in Google Books)
2. p. 432 The Story of the Irish Race by Seumas MacManus
3. War and Famine in Ireland, 1580-1700 | The Irish Story
4. McManus, pp 430-31
5. p. 20 An Introduction to Population, By Helen G. Daugherty (viewable in Google Books)
6. 1741: The Year of Slaughter | Irish History Podcast
7. pp 279-289, The Population of Ireland by K.H. Connell (Oxford 1950)
8. p. 3 New Developments in Irish Population History by Joel Mokyr and Cormac Ó Gráda. Viewable at: http://researchrepository.ucd.ie/bit...pdf?sequence=1