Had it not been for John Milton, the hobbits might never have had their peaceful lives threatened by Sauron, Harry Potter might have completed his Hogwarts education untroubled by Lord Voldemort, and Lyra might never have received the unwelcome attention of Mrs Coulter or Lord Asriel.
Born 400 years ago, Milton is the poet who brought Satan into English literature. Though other writers had conjured up minor devils, none had dared recreate the arch-fiend himself. Even the Book of Genesis, which offers an introductory course in what Satan does and why he is to be avoided, but does not tell us what he is actually like.
Then in 1667, an ageing, blind poet, whose books had been burnt by order of King Charles II, produced an epic that filled 10 volumes, and retold the story of Genesis as never before.
Before we reach line 40 of Paradise Lost we are introduced to "th' infernal Serpent", mastermind of a failed coup against the Creator, who has been "hurld headlong flaming from th' Ethereal Skie with hideous ruin and combustion down to bottomless perdition, there to dwell in Adam-antine Chains and penal Fire."
Nasty though he may be, this villain has energy and "unconquerable will". While the other cherubims are feeling rather sorry for themselves as they lie chained to a burning swamp knowing that they will never see the light of heaven again, their boss rallies with a defiant speech.
"Of this be sure," he tells them, "to do ought good never will be our task, but ever to do ill our sole delight ..." Determined to do something – anything – to upset the Almighty who has consigned them to this place, they open up a battle front on earth, where Lucifer whispers in Eve's ear and brings about the fall of the human race.
You do not need to be a literal believer in the truth of the Bible to find that Paradise Lost is a fiendishly good read.
This month, Cambridge University will stage the first of a series of special lectures to mark Milton's quatercentenary. The Bodleian Library, in Oxford, got in slightly ahead of them with a winter exhibition that will go on until April. There will also be a series of events throughout in the Church of St Giles without Cripplegate – near London's Barbican complex – where Milton, and his father, were buried.
"Milton is still with us in a profound way," Dr Gavin Alexander, a fellow of Milton's old college, Christ's, Cambridge, said.
"His writing combined the traditional modes of epic and romance with what we would now call fantasy and science fiction, telling stories about humanity on a cosmic scale that nobody had really seen before.
"That set the precedent for some of the most popular and powerful writers and film makers of the past 100 years. Without him, it's questionable that we would have ever heard of Lord of the Rings, Star Trek, or The Matrix. His idea of Satan – a flying, shape-changing superhero, magically persuasive and supernaturally powerful – could just as easily be Sylar, from Heroes. Certainly Philip Pullman's His Dark Materials trilogy could never have been written."
An earlier writer who owed a vast, acknowledged debt was William Blake, who not only wrote whole poems about Milton, but also had a close encounter of the third kind with him. Having been dead for more than a century, Milton left paradise disguised as a comet, headed for Lambeth, in south London and landed on – or in – Blake's left foot, the "sinister" foot. This startling experience enabled Blake to see, "the nether regions of the Imagination" and to, "walk on thro' eternity". Or so Blake said.
Blake was one of the first to remark on the demonic nature of Milton's poetry. "The reason Milton wrote in fetters when he wrote of "Angels & God", and at liberty when of "Devils & Hell", Blake observed, "is because he was a true poet, and of the Devil's party without knowing it."
In the turbulent century in which Milton lived, it must have been hard at times to know which side was "the Devil's party". He was born into a world in which almost everyone accepted that the word of the reigning monarch was law, and that the mysteries of religion were beyond the understanding of ordinary men, who needed priests as their intermediaries to God. But, as an adult, Milton saw these certainties smashed to pieces: the King was beheaded; England came under the rule of an iron-willed commoner, Oliver Cromwell; and men studied the Bible for themselves to reach their own interpretations of God's will.
There is no doubt which side Milton was on. His father, whom he loved and admired, had been disinherited by his Roman Catholic family for becoming a Protestant. In his late twenties, Milton travelled to Italy where, "I found and visited the famous Galileo, grown old, a prisoner of the Inquisition." He then became a convinced Puritan, opposed to the arbitrary will of kings and priests.
At the age of 34, he married17- year-old Mary Powell, whose family were royalists. She did not empathise with his bookish ways, and went back to her parents for three years. Later, they were reconciled, and had three daughters and a son. After her death, he remarried – twice.
Mary's desertion shocked Milton, who wrote a pamphlet arguing that incompatibility, and not just adultery, should be grounds for divorce, an idea that actually became law 330 years later. At the time, it caused such outrage that the government instigated a prosecution, provoking Milton to write one of the finest defences of the right to free speech in the English language. "Who kills a man kills a reasonable creature," he wrote, "but he who destroys a good book kills reason itself."
In 1649, the year after the beheading of King Charles I, Milton wrote a tract called "The Tenure of Kings and Magistrates", defending the people's right to depose and execute a bad king. A month later, he was appointed Secretary for Foreign Tongues in Oliver Cromwell's administration.
Early in the 1650s, he was afflicted by total blindness and from then on had to have documents read to him, and had to write by dictating to secretaries. This private disaster was followed by a political catastrophe, when the monarchy was restored, a warrant was issued for Milton's arrest, and an order made that all his books were to be burnt. Luckily, he had friends in court who protected him from prosecution, and friends who hid his books from the flames. Milton's tragedy was posterity's good fortune. If he had continued in public life, he might never have written Paradise Lost or its inferior sequel, Paradise Regained, or his final work, Samson Agonistes. But, embittered, blind, short of funds and out of work, he settled down to compose his epic account "of man's disobedience, and the fruit of that forbidden tree, whose mortal taste brought death into the world, and all our woe."
His routine in those final years was to get out of bed at four or five in the morning, listen to a chapter from the Bible, eat breakfast, then, until noon, dictate to his daughters or whoever else from the extended family had been roped in to act as his secretary. After an hour's walk and another hour playing the organ or viola, he worked until night. Then he would have a supper of, "olives or some light thing", a pipe, and a glass of water.
Trouble pursued Milton even after his death in 1674. In 1683, another wave of political panic swept Oxford University, whose governing body again ordered that all Milton's works were to be burnt in the Schools Quadrangle library.
Fortunately, the head of the Bodleian, John Rouse, had taken the precaution of leaving them out of the library catalogue, so the authorities did not know about treasures such as the 12-volume first edition of Paradise Lost. It will be on display in the Bodleian from 21 to 24 March.
By the following century, Milton was a cult figure, and Paradise Lost was up there with the Bible and Pilgrim's Progress as the most widely read work in the English language. He is thought to have inspired Mary Shelley when she was writing Frankenstein but singularly failed to inspire her feminist mother, Mary Wollstonecraft, who did not approve of the way Milton used his daughters as secretaries, exclaiming: "I am sick of hearing of the sublimity of Milton."
But one author who has never hidden the debt he owes to Milton is Philip Pullman, now the UK's favourite male children's author. The Bodleian invited him to kick off the year's celebrations by giving a talk to mark the poet's 399th birthday, last December. Pullman, an atheist, paid a fulsome tribute to a man whose life and work are imbued with deeply held religious beliefs.
"Four hundred years after the birth of John Milton he still lives, his example still inspires, his words still echo," he said. "Milton is our greatest public poet."