Irish campaign: 1649-1650:

Cromwell led a Parliamentary invasion of Ireland from 1649-50. Parliament's key opposition was the military threat posed by the alliance of the Irish Confederate Catholics and English royalists (signed in 1649). The Confederate-Royalist alliance was judged to be the biggest single threat facing the Commonwealth. However, the political situation in Ireland in 1649 was extremely fractured: there were also separate forces of Irish Catholics who were opposed to the royalist alliance, and Protestant royalist forces that were gradually moving towards Parliament. Cromwell said in a speech to the army Council on 23 March that "I had rather be overthrown by a Cavalierish interest than a Scotch interest; I had rather be overthrown by a Scotch interest than an Irish interest and I think of all this is the most dangerous".

Cromwell's hostility to the Irish was religious as well as political. He was passionately opposed to the Roman Catholic Church, which he saw as denying the primacy of the Bible in favour of papal and clerical authority, and which he blamed for suspected tyranny and persecution of Protestants in Europe. Cromwell's association of Catholicism with persecution was deepened with the Irish Rebellion of 1641. This rebellion, although intended to be bloodless, was marked by massacres of English and Scottish Protestant settlers by Irish and Old English, and Gallowglass Scot Catholics in Ireland (these settlers had settled on land seized from former, native Catholic owners to make way for the non-native Protestants). These factors contributed to Cromwell's harshness in his military campaign in Ireland.

Parliament had planned to re-conquer Ireland since 1641 and had already sent an invasion force there in 1647. Cromwell's invasion of 1649 was much larger and, with the civil war in England over, could be regularly reinforced and re-supplied. His nine month military campaign was brief and effective, though it did not end the war in Ireland. Before his invasion, Parliamentarian forces held only outposts in Dublin and Derry. When he departed Ireland, they occupied most of the eastern and northern parts of the country. After his landing at Dublin on 15 August 1649 (itself only recently defended from an Irish and English Royalist attack at the battle of Rathmines), Cromwell took the fortified port towns of Drogheda and Wexford to secure logistical supply from England. At the siege of Drogheda in September 1649, Cromwell's troops massacred nearly 3,500 people after the town's capture - comprising around 2,700 Royalist soldiers and all the men in the town carrying arms, including some civilians, prisoners, and Roman Catholic priests. Cromwell wrote afterwards that:

"I am persuaded that this is a righteous judgment of God upon these barbarous wretches, who have imbued their hands in so much innocent blood and that it will tend to prevent the effusion of blood for the future, which are satisfactory grounds for such actions, which otherwise cannot but work remorse and regret."

At the Siege of Wexford in October, another massacre took place under confused circumstances. While Cromwell was apparently trying to negotiate surrender terms, some of his soldiers broke into the town, massacred 2,000 Irish troops and up to 1,500 civilians, and burned much of the town. The size of this force must have been substantial in order to defeat 2000 troops, which casts doubt on the claim of sincere negotiation on behalf of Cromwell. It is notable that no disciplinary actions were taken against his forces subsequent to this second massacre.

After the massacre of Drogheda, Cromwell sent a column north to Ulster to secure the north of the country and went on to besiege Waterford, Kilkenny and Clonmel. Kilkenny surrendered on terms, as did many other towns like New Ross and Carlow, but Cromwell failed to take Waterford and at the siege of Clonmel in May 1650, he lost up to 2,000 men in abortive assaults before the town surrendered. One of his major victories in Ireland was diplomatic rather than military. With the help of Roger Boyle, 1st Earl of Orrery, Cromwell persuaded the Protestant Royalist troops in Cork to change sides and fight with the Parliament. At this point, word reached Cromwell that Charles II had landed in Scotland and been proclaimed king by the Covenanter regime. Cromwell therefore returned to England from Youghal on 26 May 1650 to counter this threat.

The Parliamentarian conquest of Ireland dragged on for almost three years after Cromwell's departure. The campaigns under Cromwell's successors Henry Ireton and Edmund Ludlow mostly consisted of long sieges of fortified cities and guerrilla warfare in the countryside. The last Catholic held town, Galway, surrendered in April 1652 and the last Irish troops capitulated in April of the following year.

In the wake of the Commonwealth's conquest, the public practice of Catholicism was banned and Catholic priests were murdered when captured. In addition, roughly 12,000 Irish people were sold into slavery under the Commonwealth. All Catholic-owned land was confiscated in the Act for the Settlement of Ireland 1652 and given to Scottish and English settlers, the Parliament's financial creditors and Parliamentary soldiers. The remaining Catholic landowners were allocated poorer land in the province of Connacht - this led to the Cromwellian attributed phrase "To hell or to Connacht". Under the Commonwealth, Catholic landownership dropped from 60% of the total to just 8%.

Debate over Cromwell's effect on Ireland:

The extent of Cromwell's brutality in Ireland has been strongly debated. Some historians argue that Cromwell never accepted that he was responsible for the killing of civilians in Ireland, claiming that he had acted harshly, but only against those "in arms". Other historians, however, cite Cromwell's contemporary reports to London including that of 27 September 1649 in which he lists the slaying of 3,000 military personnel, followed by the phrase "and many inhabitants". In September 1649, he justified his sack of Drogheda as revenge for the massacres of Protestant settlers in Ulster in 1641, calling the massacre "the righteous judgement of God on these barbarous wretches, who have imbued their hands with so much innocent blood." However, Drogheda had never been held by the rebels in 1641 - many of its garrison were in fact English royalists. On the other hand, the worst atrocities committed in Ireland, such as mass evictions, killings and deportation of over 50,000 men, women and children for indentured labour to Bermuda and Barbados, were carried out under the command of other generals after Cromwell had left for England. On entering Ireland, Cromwell demanded that no supplies were to be seized from the civilian inhabitants, and that everything should be fairly purchased; "I do hereby warn....all Officers, Soldiers and others under my command not to do any wrong or violence toward Country People or any persons whatsoever, unless they be actually in arms or office with the enemy.....as they shall answer to the contrary at their utmost peril." Several English soldiers were hanged for disobeying these orders.

While the massacres at Drogheda and Wexford were in some ways typical of the day, especially in the context of the recently ended Thirty Years War which reduced the male population of Germany by up to half, there are few comparable incidents during Parliament's campaigns in England or Scotland. One possible comparison is Cromwell's siege of Basing House in 1645 - the seat of the prominent Catholic the Marquess of Winchester - which resulted in about 100 of the garrison of 400 being killed after being refused quarter. Contemporaries also reported civilian casualties, six Catholic priests and a woman. However, the scale of the deaths at Basing House was much smaller. Cromwell himself said of the slaughter at Drogheda in his first letter back to the Council of State: "I believe we put to the sword the whole number of the defendants. I do not think thirty of the whole number escaped with their lives." Cromwell's orders  -  "in the heat of the action, I forbade them to spare any that were in arms in the town"  -  followed a request for surrender at the start of the siege, which was refused. The military protocol of the day was that a town or garrison that rejected the chance to surrender was not entitled to quarter. The refusal of the garrison at Drogheda to do this, even after the walls had been breached, was to Cromwell justification for the massacre. Where Cromwell negotiated the surrender of fortified towns, as at Carlow, New Ross, and Clonmel, he respected the terms of surrender and protected the lives and property of the townspeople. At Wexford, Cromwell again began negotiations for surrender. However, the captain of Wexford castle surrendered during the middle of the negotiations, and in the confusion some of his troops began indiscriminate killing and looting. Amateur Irish historian (and Drogheda native) Tom Reilly has taken this argument further, claiming that the accepted versions of the campaigns in Drogheda and Wexford in which wholesale killings of civilians on Cromwell's orders took place "were a 19th century fiction". However, Reilly's conclusions have been rejected by other scholars.

Although Cromwell's time spent on campaign in Ireland was limited, and although he did not take on executive powers until 1653, he is often the central focus of wider debates about whether, as historians such as Mark Levene and John Morrill suggest, the Commonwealth conducted a deliberate programme of ethnic cleansing in Ireland. By the end of the Cromwellian campaign and settlement there had been extensive dispossession of landowners who were Catholic, and a huge drop in population.

The sieges of Drogheda and Wexford have been prominently mentioned in histories and literature up to the present day. James Joyce, for example, mentioned Drogheda in his novel Ulysses: "What about sanctimonious Cromwell and his ironsides that put the women and children of Drogheda to the sword with the bible text God is love pasted round the mouth of his cannon?" Similarly, Winston Churchill described the impact of Cromwell on Anglo-Irish relations:

...upon all of these Cromwell's record was a lasting bane. By an uncompleted process of terror, by an iniquitous land settlement, by the virtual proscription of the Catholic religion, by the bloody deeds already described, he cut new gulfs between the nations and the creeds. 'Hell or Connaught' were the terms he thrust upon the native inhabitants, and they for their part, across three hundred years, have used as their keenest expression of hatred 'The Curse of Cromwell on you.' ... Upon all of us there still lies 'the curse of Cromwell'."

Cromwell is still a figure of hatred in Ireland, his name being associated with massacre, religious persecution, and mass dispossession of the Catholic community there. As Churchill notes, a traditional Irish curse was malacht Cromail ort or "the curse of Cromwell upon you".

The key surviving statement of Cromwell's own views on the conquest of Ireland is his Declaration of the lord lieutenant of Ireland for the undeceiving of deluded and seduced people of January 1650. In this he was scathing about Catholicism, saying that "I shall not, where I have the power... suffer the exercise of the Mass." However, he also declared that: "as for the people, what thoughts they have in the matter of religion in their own breasts I cannot reach; but I shall think it my duty, if they walk honestly and peaceably, not to cause them in the least to suffer for the same." Private soldiers who surrendered their arms "and shall live peaceably and honestly at their several homes, they shall be permitted so to do." As with many incidents in Cromwell's career, there is debate about the extent of his sincerity in making these public statements: the Rump Parliament's later Act of Settlement of 1652 set out a much harsher policy of execution and confiscation of property of anyone who had supported the uprisings.

Death and posthumous execution:

Cromwell is thought to have suffered from malaria (probably first contracted while on campaign in Ireland) and from "stone", a common term for urinary/kidney infections. In 1658 he was struck by a sudden bout of malarial fever, followed directly by illness symptomatic of a urinary or kidney complaint. A Venetian physician tracked Cromwell's final illness, saying Cromwell's personal physicians were mismanaging his health, leading to a rapid decline and death. The decline may also have been hastened by the death of his favourite daughter, Elizabeth Claypole, in August. He died aged 59 at Whitehall on Friday 3 September 1658, the anniversary of his great victories at Dunbar and Worcester. The most likely cause of Cromwell's death was septicaemia following his urinary infection. He was buried with great ceremony, with an elaborate funeral based on that of James I, at Westminster Abbey, his daughter Elizabeth also being buried there.

He was succeeded as Lord Protector by his son Richard. Although Richard was not entirely without ability, he had no power base in either Parliament or the Army, and was forced to resign in May 1659, ending the Protectorate. There was no clear leadership from the various factions that jostled for power during the short lived reinstated Commonwealth, so George Monck, the English governor of Scotland, at the head of New Model Army regiments was able to march on London, and restore the Long Parliament. Under Monck's watchful eye the necessary constitutional adjustments were made so that in 1660 Charles II could be invited back from exile to be king under a restored monarchy.
In 1661, Oliver Cromwell's body was exhumed from Westminster Abbey, and was subjected to the ritual of a posthumous execution, as were the remains of John Bradshaw and Henry Ireton. (The body of Cromwell's daughter was allowed to remain buried in the Abbey.) Symbolically, this took place on 30 January; the same date that Charles I had been executed. His body was hanged in chains at Tyburn. Finally, his disinterred body was thrown into a pit, while his severed head was displayed on a pole outside Westminster Hall until 1685. Ironically the Cromwell vault was then used as a burial place for Charles II's illegitimate descendants. Afterwards the head changed hands several times, including the sale in 1814 to a man named Josiah Henry Wilkinson, before eventually being buried in the grounds of Sidney Sussex College, Cambridge, in 1960.