A near complete conquest of Ireland is achieved by the turn of the seventeenth century, following the Nine Years' War and the Flight of the Earls.

This control is further consolidated during the wars and conflicts of the seventeenth century, which witnesses English and Scottish colonization in the Plantations of Ireland, the Wars of the Three Kingdoms and the Williamite War.

Irish losses during the Wars of the Three Kingdoms (which, in Ireland, include the Irish Confederacy and the Cromwellian conquest of Ireland) are estimated to include twenty thousand battlefield casualties. 

Two hundred thousand civilians are estimated to have died as a result of a combination of war-related famine, displacement, guerrilla activity and pestilence over the duration of the war.

A further fifty thousand are sent into indentured servitude in the West Indies.

Some historians estimate that as much as half of the pre-war population of Ireland may have died as a result of the conflict.

Northwest Europe (1636–1647 CE): Civil Strife, Colonial Expansion, and Intellectual Achievement

England: Civil War and Turmoil

The tensions between Charles I and Parliament culminated in open conflict with the outbreak of the English Civil War in 1642. The king's authoritarian policies, religious controversies, and resistance to parliamentary authority led to a brutal struggle between Royalists (supporters of the monarchy) and Parliamentarians (advocates of parliamentary governance). Prominent leaders such as Oliver Cromwell emerged, significantly influencing the Parliamentarian cause. Battles such as Edgehill (1642), Marston Moor (1644), and Naseby (1645) were pivotal, ultimately resulting in Charles's defeat and subsequent imprisonment.

Ireland: Rebellion and Conflict

In 1641, Ireland erupted into rebellion as the Catholic Gaelic and Old English populations sought to reverse decades of plantation policies and Protestant domination. This uprising swiftly escalated into the Irish Confederate Wars, intertwining with the broader conflicts across Britain and Ireland, further complicating the turbulent political landscape.

Scotland: Covenanters and Wars of the Three Kingdoms

Scotland, deeply affected by Charles I's religious policies, witnessed the outbreak of the Bishops' Wars in 1639 and 1640, driven by Presbyterian Covenanters resisting Anglican influence. By 1643, Scotland allied formally with the English Parliamentarians through the Solemn League and Covenant, playing a critical role in shaping the outcome of the civil wars across the British Isles.

Scandinavia: Denmark-Norway’s Continuing Struggles

Christian IV struggled to restore Danish influence following earlier military defeats. Although he pursued internal reforms and fortifications, Denmark-Norway remained politically weakened, grappling with ongoing economic and military setbacks that constrained its ambitions in European affairs.

Maritime and Colonial Developments

The English East India Company expanded its commercial presence in India significantly during this period. The hospitality initially extended by the Mughal emperor Jahangir was further consolidated under his successor Shah Jahan, resulting in increased English influence and the expansion of trade networks, particularly in commodities like cotton, silk, indigo, and tea. Concurrently, English colonial ventures in North America continued to flourish, with Massachusetts Bay Colony and other New England settlements experiencing substantial growth, laying foundational structures for future American colonial expansion.

Scientific and Intellectual Advances

The period remained intellectually vibrant, marked by ongoing developments in natural philosophy and science. The legacy of Francis Bacon’s inductive methods continued to inspire researchers, while significant strides were made in mathematics and astronomy. In 1637, René Descartes published Discourse on Method, greatly influencing European thought, including intellectual circles in Northwest Europe.

Cultural Flourishing Amidst Conflict

Despite political upheaval, cultural life in Northwest Europe persisted robustly. Literature thrived, with the emergence of works such as John Milton’s early poetry, reflecting the intense religious and political debates of the era. Music and theater continued to evolve, capturing the complexities and turbulence of contemporary society.

Legacy of the Era

By 1647 CE, Northwest Europe was profoundly transformed. England stood on the precipice of a republic as Charles I awaited trial and the balance of power shifted decisively toward Parliament. Ireland and Scotland remained entangled in complex conflicts tied to broader struggles across the British Isles. Meanwhile, the region's cultural and intellectual advancements set the stage for future developments, marking the era as one of profound transition.

The Long Parliament, which has religious concerns similar to those of the Scots, refuses to vote for new taxes to pay for raising an army.

Charles therefore starts negotiations with Irish Catholic gentry to recruit an Irish army to put down the rebellion in Scotland, in return for the concession of Irish Catholics' longstanding requests for religion toleration and land security.

To the Scots and the English Parliaments, this appears to confirm that Charles is a tyrant, who wants to impose Catholicism on his kingdoms, and to govern again without reference to his Parliaments as he had done in 1628–1640.

Some Scots and Parliamentarians during the early part of 1641, seven propose invading Ireland and subduing organized Catholicism there, to ensure that no royalist Irish Catholic army would land in England or Scotland.

A small group of Irish Catholic landowners, frightened by this, and wanting to seize the opportunity, conceive a plan to take Dublin Castle and to control other important towns around the country in a quick coup in the name of the King, both to forestall a possible invasion and to force him to concede the Catholics' demands.

Also, Charles' failure to defeat the Scots and the pressure he and his ministers have been under from the "Short" and "Long" English parliaments in 1640–41, make him appear weak and make it appear it much more likely that a rebellion would be successful.

The Scots have watched as England has slipped ever deeper into political quicksand in the weeks and months that followed the conclusion of the Second Bishops' War and the summoning of the Long Parliament.

What Charles gains with one hand he inevitably loses with the other.

It is sometimes argued that the Covenanters wished to recast the whole of Britain in their own Presbyterian image.

It is certainly true that they had been pressing for a full-scale reform in the English church since 1641, though this is not for the reasons usually given.

The Scots are as aware as the king that a political and religious settlement in one part of the realm cannot be maintained in perfect isolation from another.

It is a question, above all, of security.

In the hopes of winning Scottish support, Charles goes to Scotland in the autumn of 1641 where he gives titles to Leslie and Argyll, and accepts all the decisions of the General Assembly of 1638 and of the Scottish Parliament of 1641, including confirming the right of the Parliament to challenge the actions of his ministers.

He has now withdrawn all the causes of the original dispute, but within a year his disputes with the English Parliament will lead to civil war.

The Root and Branch bill is defeated after lengthy debates in August 1641.

The Old English within the Irish Parliament argue, in a similar manner as pursued by the English Parliament in their opposition to Buckingham, albeit from a far less disingenuous stance, that their opposition to Strafford had not negated their loyalty to Charles.

Their position is that Charles, rather, had been led astray by the malign influence of the Earl, and that, moreover, the ambiguity surrounding Poynings' Law meant that, instead of ensuring that the king was directly involved in the governance of Ireland, that a viceroy such as Strafford, the Earl of Wentworth, could emerge as a despotic figure.

However, the New English settlers in Ireland are Protestant, unlike their Old English counterparts who are Catholic, and can loosely be defined as aligned with the English Parliament and the Puritans; thereby fundamentally opposed to the crown due to unfolding events within England herself.

Various disputes between native and colonizer concerning fallout from the most recent plantation of Ulster, coupled with the gradual polarization of monarchist and anti-monarchist, will sow the seeds of conflagration in Ireland that, despite its initial chaos, provides the catalyst for direct armed combat within England between those who oppose the authority of the king and those who support it.

The success of the trial against Strafford has weakened Charles' influence whilst also paving the way for cooperation between the Gaelic Irish and Old English in Ireland, who have hitherto been antagonistic towards one another.

Thus, in the conflict between the Gaelic Irish and New English settlers in the Irish Rebellion of 1641, the Old English side with the Celtic Irish whilst simultaneously professing their loyalty to the king.

Charles hopes to make common cause against the English Long Parliament with Archibald Campbell, the Earl of Argyll and the effective leader of the Presbyterian Covenanters, and creates him Marquess of Argyll.

The Marquis of Hamilton, while remaining a Royalist, seeks to develop a friendship with the Marquess of Argyll.

It is not clear how much Charles I approved of this liaison, but many in the Scottish Royalist faction feel threatened by this development.

Lord Henry Ker (the son of the Earl of Roxburgh), riding into Edinburgh at the head of an armed retinue on the evening of September 29, challenges Hamilton to a duel, calling him a traitor.

The episode ends without violence as Lord Ker backs down and apologizes.

It sets in motion among others, however, Royalist murmurs and whispers that lead to plotting.

The plot, directed against the Marquess of Argyll, the Marquess of Hamilton, and his brother the Earl of Lanark, is hatched by the Royalist, and rival of Argyll, the Earl of Montrose, who had already attempted to have Argyll charged with high treason.

The three are to be kidnapped and taken on board a ship at Leith, but on October 11, General Leslie, the leader of the Covenanter army, is informed of the plot by Sir John Hurry, a Scottish soldier who had been invited to join the conspiracy.

Argyll, Hamilton and Lanark are forced to flee from Edinburgh to Hamilton's property at Kinneil House, near Bo'ness.

The next day, Charles denies any involvement in the plot—or , as it is soon called, the Incident—and is soon forced to allow an investigation into the matter.

Charles is left with no option but to submit to the Covenanters' demands.

He assents to the abolition of episcopacy in Scotland, and appoints Covenanting nobles to the Privy Council of Scotland and other positions, before returning to England in November to face the increasing threat of civil war.

The first of the Stewart Kingdoms to collapse into civil war is Ireland, where, prompted in part by the anti-Catholic rhetoric of the Covenanters, Irish Catholics launch a rebellion in October.

In reaction to Charles I's and Thomas Wentworth's proposal to raise an army manned by Irish Catholics to put down the Covenanter movement in Scotland, the Parliament of Scotland had threatened to invade Ireland in order to achieve "the extirpation of Popery out of Ireland" (according to the interpretation of Richard Bellings, a leading Irish politician).

The fear this causes in Ireland once the rebellion has broken out unleashes a wave of massacres against English and Scottish Protestant settlers.

The planners of the rebellion are a small group of Irish landowners, mainly Gaelic Irish and from the heavily planted province of Ulster.

Hugh Og MacMahon and Conor Maguire are to seize Dublin Castle, while Phelim O’Neill and Rory O’Moore are to take Derry and other northern towns.

The plan, to be executed on October 23, 1641 (Roman Catholic Feast of St. Ignatius of Loyola), is to use surprise rather than military force to take their objectives, then, in expectation of support from the rest of the country, to issue their demands.

The plan for a fairly bloodless seizure of power is foiled, however, when the authorities in Dublin hear of the plot from an informer (a Protestant convert named Owen O’Connolly) and arrest Maguire and MacMahon.

O'Neill meanwhile goes ahead and starts the rebellion in the north of the country, capturing the important fort of Charlemont, one of only a handful of modern fortresses to be found in Ireland at that time, claiming to be acting in the King's name.

He quickly finds, however, that he cannot control the Irish Catholic peasantry he has raised.

These people, many of whom had been displaced during the Plantation of Ulster, begin attacking the Scottish and English Protestant settlers.