MILTON WROTE FROM the heat, and the heart, of the 17th century. The world was all around him. He was a London visionary who, like William Blake and Thomas More, derived his strength and independence from his life in the city. He was born in 1608, in a house along Bread Street in the City of London. His father was a successful scrivener, a now-extinct trade that combined the duties of accountant, broker and estate agent. He was a successful tradesman, but he reserved his greatest ambition for his son. From the age of five Milton began a process of scholarship and study that would continue for the rest of his life.

As a boy he studied so hard that he rarely retired to bed before midnight. He attended Saint Paul's School, 100 yards or so from his house, and there he absorbed Latin, Greek, Hebrew, French and Italian. The immediate milieu was suffused with words and makers of words. The bookshops were in the churchyard of Saint Paul's. Young Milton might have passed Shakespeare in the street. He would certainly have recognised John Donne, who became Dean of Saint Paul's. In this entertaining and intelligent study Anna Beer does a good job of reconstructing the texture and atmosphere of early 17th-century London.

At the age of 16 he passed on to Christ's College, Cambridge, where his feminine good looks earned him the title of “The Lady of Christ's”. It was an age of religious dispute, during which the more active and eloquent people of the nation engaged in passionate debate about the nature of Catholicism, Protestantism and the whole range of religious dissent. No one (or hardly anyone) was an unbeliever. The life of the mind was inseparable from the notions of piety and prayer. It was also tied inextricably to the use of the Latin language, of which tongue Milton was a master. Most of his earliest poems are composed in that language, and he was able to write it as fluently as he wrote English. At the same time he was writing sonnets in Italian, directed principally at his close friend, Charles Diodati, with whom he shared that deep and sexless intimacy that was then so common among males.

Milton preserved all of these early poems as signs of his manifest destiny. He believed earnestly in his own fame and fate, and knew that providence would guide him. Immediately after leaving Cambridge, however, he seemed uncertain. He did not want a life of leisure. He hated leisure, and despised those who frittered away their time. “What am I pondering, you ask?” he told Diodati. “God help me, immortality.” Never has a writer been so fixed upon his future fame. If his idea of “immortality” is also imbued with the notion of Christian salvation, then we may come closer to understanding the union between Milton's private ambition and public religious sensibility.

Then, as part of his continuing literary education, he travelled to Italy. Anna Beer is particularly astute on the cultural and intellectual life of the time, placing Milton firmly in the context of Protestant humanism. He returned to England in 1639, at a time when the country had drawn dangerously close to civil war. It was time for Milton to play his part. Yet he knew that he had “greater strength of mind than of body”, as he put it. So he used a pen rather than a sword. He turned from poetry to prose; he eschewed Latin for the sake of English. In the phrase of Beer he “almost single-handedly created the identity of the writer as political activist”. In other words he became a pamphleteer, obscene and pugnacious in equal measure. He could be offensive, vulgar and vicious.

We may pause now for a domestic interval, albeit a short one. At the age of 33 in 1642, he married a woman of 17. Nothing in his life seems to have prepared him for such a move, but nonetheless he took it. But husband and wife lived together for only a month before the young woman returned to her family. In this period, in fact, he wrote a pamphlet extolling the virtues of divorce. Scholars have argued whether these two events are related. In anyone less high-minded than Milton, the connection would be plain. Yet his public and private worlds are so intermingled that no final determination is possible.

In that same year, civil war between King and Parliament began. Milton was caught up in the general conflict. His pamphlets against the King were condemned as licentious and irreligious. Yet nothing could prevent him from speaking to a nation deemed to be under peril from the forces of superstition and unreason. He became what Beer calls a “revolutionary republican” and, six weeks after the execution of Charles I, he accepted the post of Secretary for Foreign Tongues in Cromwell's Government. He dealt with all the Latin correspondence, of course, but in his tracts and pamphlets he became the voice of republican England throughout Europe.

He was also eloquent on the subject of his newest affliction. Even as he was defiantly engaged with the world he sensed that blindness was coming. “Then let us bear it,” he wrote. “To be blind is not miserable, not to be able to bear blindness, that is miserable.” His eyes became weak and dim. His wife returned to him. He eventually became a father to three daughters - very little is known about them. Some say that they despised their father; others claim that they admired and supported him. As with all of Milton's private affairs, there is mystery here. That was the way he wanted it. He saw himself in objective terms, as a living metaphor, treating himself almost impersonally.

When Cromwell died in the early autumn of 1658, Milton's political world died with him. On the return of the King, in the spring of 1660, the poet went into hiding. His books were burnt by the public hangman at the Old Bailey, a most inauspicious event. He was exempted from the death penalty, but when he emerged from hiding he was arrested and imprisoned for two months.

There could be no more tracts, no more pamphlets. Instead he began work on a subject upon which he had mused in his cell and in his blindness, a biblical epic on the loss of paradise.

Beer gives a persuasive reading of the power and complexity of Paradise Lost, arguably the greatest religious poem in the English language. It was followed three years later by Paradise Regained, Samson Agonistes and a History of Britain. Claire Tomalin's new selection of poems provides a good introduction to the music of John Milton, but those harmonies are to be found in his prose as well as his verse.

All of his works were of a piece, a long symphony that ended only at his death. His writing is as eloquent and as engaging as it ever was. Milton was sure of his own genius, and he knew that he would triumph in the end.

Milton: Poet, Pamphleteer & Patriot by Anna Beer
Bloomsbury, £20

Poems of John Milton edited by Claire Tomalin
Penguin Classics, £10.99

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