The many tensions which came to a head in the English Civil War (1642–48) had been building for a half-century or more. The ascent of James I to the throne in 1603 inaugurated a profound cultural shift as Elizabeth's styles of self-representation were replaced by those of a king who defined himself as an absolute monarch and God's anointed deputy, through several cultural roles. Already an author, James reprinted at the time of his accession his True Law of Free Monarchies (originally published in 1598), defending royal absolutism grounded on the divine right of kings. In his very elaborate coronation procession through the City of London, he passed through spectacular Roman triumphal arches at various stages, thereby identifying himself as a new Augustus. That Roman style was emphasized by the designer Inigo Jones in sets for court masques and in new buildings such as the banqueting hall at Whitehall, the site for many such masques. An early court entertainment, Jonson's Masque of Blackness (1605), represented James as a sun king. James also portrayed himself as patriarch-king: in the Basilikon Doran (1601), addressed to the heir apparent, Prince Henry, and in the often-revised portrait of his family, shown here. Figures reclining on one arm have died: James's queen, Anne of Denmark, is so shown, as is Prince Henry, whose death dashed the hopes of the many reformist Protestants who saw in him a leader in the struggle against Rome. At the left stands the new heir, Prince Charles, and his queen, the French Catholic Henrietta Maria. At the right, James's daughter, Elizabeth, and her husband Frederick, Elector Palatine — staunch Protestants whose claims to the throne of Bohemia touched off the thirty-year war between Catholic and Protestant powers on the continent. Descendants of their numerous progeny soon peopled the thrones of Europe, including England (with George I in 1714).

Conflicts over styles of belief and devotion, already present in Elizabeth's realm, intensified with James's accession, though most English people remained within the established church. Controversies regarding doctrine (predestination vs. free will), worship (the Book of Common Prayer or an emphasis on preaching and reformed ritual), and ecclesiastical structures (bishops or Presbyterian synods) form a subtext to much religious poetry of the period — Donne, Herbert, Vaughan, Crashaw. Such controversies are also visually represented in different kinds of emblems, a popular multimedia form combining text and picture, and often suggestive for the poetic imagery of the period. One flashpoint in the conflict over culture was the Book of Sports, issued by James I in 1618 and reissued by Charles I in 1633, explicitly authorizing and promoting the Sunday sports and rural festivals denounced by many Puritans as profanations of the sabbath, pagan in origin, and occasions of sin. William Prynne's notorious Histrio-Mastix (1633), published a few months before Charles reissued the Book of Sports, voices the most extreme Puritan denunciation of both rural and court culture — not only maypoles, mumming, and Sunday sports but also court masques and stage plays; Prynne was brutally punished for this direct affront to the monarchs. In the 1660s the Puritan historian Lucy Hutchinson supplied a retrospective account and interpretation of these culture wars and their political and religious import.

As the 1630s wore on, Puritans of various kinds pressed for more reformation in doctrine, worship, and church government to eradicate "idolatrous" and "papist" elements (bishops, liturgy, altars, religious icons) while Charles I's Archbishop of Canterbury, William Laud, imposed those elements ever more strictly. When war broke out in 1642, Puritans of all sorts portrayed England as a new Israel whose people would replicate in some ways the experience of that other chosen people. A much-contested issue concerned the duty of the Christian magistrate toward religion: should he establish the "true" church and root out blasphemy and heresy as Church of England bishops and most Presbyterians thought (see Milton's poem On the New Forcers of Conscience [NAEL 8, 1.1826–27])? Should he offer wide toleration outside an established church, as some sectaries (and Milton) thought? The most far-reaching defense of complete religious liberty and entire separation of church and state is Roger Williams's Bloody Tenet of Persecution (1644), which draws in interesting ways on his experiences in America. Milton's Areopagitica, published the same year (NAEL 8, 1.1816–25), argues the tolerationist case on somewhat different grounds.

On the political side, the central issue became the location of sovereign power in the state. James's literary defenses of royal absolutism grounded on the divine right of kings were kept in play by Charles I, who insisted on his absolute prerogatives as a monarch and governed without a parliament for eleven years. Opponents of Charles developed a countertheory that placed supremacy in the people's representative, the Parliament and later the Commons. These two theories were acted out dramatically at the trial of Charles I: the king by argument and gesture refused to recognize the authority of the court appointed by a segment of the Commons to try him, while the court president, John Bradshaw, insisted on the court's authority as deriving from the people's representative. The execution of an anointed king on January 30, 1649, was a stupendous matter, graphically portrayed in many contemporary accounts and pictures. The need to defend the regicide and the new commonwealth "without King or House of Lords" prompted Milton to give forceful expression, in The Tenure of Kings and Magistrates (February 1649), to a radical contract theory of government analogous to that developed by contemporary republicans and Levellers: sovereignty always resides in the people, who merely delegate power to, and can always revoke it from, any ruler or any government system. Alternatively, Thomas Hobbes (NAEL 8, 1.1596–1605) developed in Leviathan (1651) a theory of absolutism based on irreversible compact, whereby the people give over all their power and right to a sovereign, whether a king or some other ruling entity, who incorporates and acts for them all.

Linking both politics and religion was the ongoing conflict about idolatry and iconoclasm in religion but also in the civic realm, around the issue of sacred kingship and the supposed sacrilege of executing an anointed king. A book purportedly written by King Charles and published immediately after his execution, Eikon Basilike [The King's Image], presents in its text and especially its frontispiece Charles as holy martyr and suffering Christ; that work prompted Milton's fierce denunciation of this "idol" in his Eikonoklastes [The Image Breaker]. Milton's post-Restoration closet drama Samson Agonistes (1674) contains an exchange on the issue of idolatry that resonates with the dilemmas of conscience faced by Puritan dissenters when they were denied toleration and faced stringent penalties for refusing to worship in the established church.