In the summer of 1725 a peculiar youth was found near the forest of Hertswold near Hameln in northern Germany. Aged about 12, he walked on all fours and fed on grass and leaves. "A naked, brownish, black-haired creature", he would run up trees when approached and could utter no intelligible sound. The latest in a long line of feral children - in turn celebrated, shunned and cursed through the ages - "The Wild Boy of Hameln" would be the first to achieve real fame.

After a spell in the House of Correction in Celle, the boy was taken to the court of George, Duke of Hanover and King of the United Kingdom, at Herrenhausen. There, the young curiosity was initially treated as an honoured guest. Seated at table with the King, in a suit of clothes with a napkin at this neck, he repelled his host with his complete lack of manners. He refused bread, but gorged himself on vegetables, fruit and rare meat, greedily grasping at the dishes and eating noisily from his hands, until he was ordered to be taken away. He was given the name of Peter, but was variously known as the "Wild Peter", "Peter of Hanover", or, most famously, "Peter the Wild Boy".

In the spring of 1726, after briefly escaping back to the forest, Peter was brought to London, where his tale had aroused particular interest. As in Hanover, he caused a sensation and his carefree nature provided an amusing antidote to the stultifying boredom and decorum of court life. He appealed especially to Princess Caroline, who persuaded the King to allow him to move to her residence in the West End, where he was kept virtually as a pet. Though he insisted on sleeping on the floor, he was dressed carefully each morning in a tailor-made suit of green and red. He was also appointed a tutor, who had him baptised and taught him to bow and kiss the hands of the ladies at court.

Peter quickly became a celebrity. On one level, tales of his antics busied the London gazettes. Jonathan Swift, whose fictional 'Yahoos' Peter appeared to personify, noted sourly that "there is scarcely talk of anything else". But, Peter also became the subject of much educated enquiry into the nature of mankind. Daniel Defoe was inspired to write the pamphlet Mere Nature Delineated, which mused on Peter's 'humanity' and whether he could possess a soul. Peter soon became the 'talk of the town', and his portrait soon graced the walls of Kensington Palace and an effigy of him was erected in a waxworks on the Strand. In 1727, a premature report of his death gave rise to a mocking epitaph in the British Journal. His similarity to Swift's fantastical characters had clearly not been missed:

"Ye Yahoos mourn, for in this Place
Lies dead the Glory of your Race,
One, who from Adam had Descent,
Yet ne'er did what he might repent;
But liv'd, unblemish'd, to fifteen,
And yet, O strange, a Court had seen,
Was solely rul'd by Nature's Laws,
And dy'd a Martyr in her Cause!
Now reign, ye Houynhnms, for Mankind,
Have no such Peter left behind,
None like the dear departed Youth,
Renown'd for Purity and Truth,
He was your Rival, and our Boast,
For ever, ever, ever lost!"

But Peter could not to live up to the popular interest invested in him and a fickle public quickly abandoned him in favour of the next unfortunate. His academic progress also failed to match his earlier promise. He was declared "unable to receive instruction", despite the attentions of "the ablest masters". He could say nothing beyond his own name and a garbled form of 'King George'. By 1728, his tutor had given up his efforts, and Peter was retired to the country. A home was found for him on a farm near Northchurch in Hertfordshire and a generous Crown pension of £35 per annum was supplied for his upkeep. The 'talk of the town' became a humble farm hand.

Though still only an adolescent, Peter faded into provincial obscurity and thereafter rarely troubled the gossip columns. He developed a taste for gin and loved music, reportedly swaying and clapping with glee and dancing until he was exhausted. But he never learned to speak and his lack of any sense of direction gave cause for concern. In 1745 he was arrested as a suspected Highlander, and, six years later, he wandered as far as Norwich, where he was thought to be a Spanish subversive. As a result, he was fitted with a heavy leather collar bearing the inscription: "Peter, the Wild Man of Hanover. Whoever will bring him to Mr Fenn at Berkhamsted, Hertfordshire, shall be paid for their trouble." He finally expired, aged around 72, in 1785.

Though Peter's life is remarkable enough, what is most astounding perhaps is the sheer scale of scientific and philosophical interest that his case aroused. Whilst wits opined that the boy might be corrupted by the sybaritic life of London high society, others saw in him an ideal test case for the nascent sciences of anthropology and psychology.

To the thinkers of the Age of Reason, Peter represented a blank slate, a tabula rasa. As humanity in its 'raw' state, he was what Rousseau called "the noble savage", man 'unspoilt' by society and civilisation. He was indeed a fascinating subject, but he provoked further, disquieting, enquiry. He was undoubtedly human, but, lacking speech and socialisation, could he be classed as a man? Could he have a soul? Could he possess the power of thought?

Of the numerous thinkers and writers who addressed the subject, Daniel Defoe did so with the most clarity. His Mere Nature Delineated, published in 1726, described Peter as an object of pity but cast doubt on the story of his origins, dismissing it as a Fib. On the issue of Peter's soul, he was more charitable. Possessed of the gift of laughter and thought, Peter clearly had a soul, he wrote, but its powers did not yet act within him. He was, in sum, in a state of Mere Nature…a ship without a Rudder. And it was the task of his tutors to bring him to the Use of his Reason. He deferred the final verdict on Peter, therefore, to the results of his education. If he could receive instruction - if he could be taught to heed his soul - then he would become a man. And, what was more, he would be a lesson to us all, especially, wrote Defoe, those who think nobody so wise as themselves.

Defoe wrestled manfully with the uncomfortable question that Peter posed - What was it that divided 'us' from 'them' - man from the animals? Different minds arrived at different conclusions. But, the habitual tidier of nature, Carl Linnæus, was typical. He reassured mankind by creating a separate species of 'wild men' or homo ferens. Peter was still clearly an outsider - one of 'them'.

Peter's example was later used in numerous theories of child development, socialisation and the role of language. Many thinkers dwelt on his inability to learn to speak. Lord Monboddo presented him as an illustration of his theory of the evolution of language in the human species. He saw Peter as evidence that man was born mute, and that articulation is altogether…a habit acquired by custom and exercise. To others, Peter was thought to demonstrate the existence of a 'critical window' in which language and other skills are developed in the child. Having missed the 'window', Peter could never learn such skills again. Hence the apparent failure of his esteemed tutors.

Other scientists concentrated on the role of 'socialisation' in child development. After a childhood supposedly devoid of parental care and nurture, Peter was considered to have developed a "mental indifference", and a lack of empathy, reflection and memory. In common with other feral children, it was argued, he "lived solely to survive", satisfying only his base desires for food and sleep. In other interpretations, Peter's mental shortcomings were attributed primarily to his lack of language. Having never learned to speak, it was suggested, how could he comprehend his own 'inner voice'? How could he order and make sense of his world? The result was that he was virtually unable to display higher mental functions. He was trapped in the mind of a toddler.

Such speculation was dented by the 19th century German anthropologist, Blumenbach, who spoiled the intellectual party by concluding that Peter was most probably mentally retarded. He examined contemporary accounts, which suggested that Peter had been tongue-tied (hence his inability to speak) and had webbed fingers on one hand (a common physical corollary to mental impairment). Moreover, Blumenbach argued, if Peter was retarded, this would help to explain his peculiar origins - a point that had also bothered Defoe. Rather than being a genuine 'feral child' then, Peter was most probably abandoned, possibly only weeks before his 'discovery'. Most importantly, however, if he had been mentally disabled, then all the noble theories of development and socialisation, which relied on his example, were rendered lame. The tabula rasa had been nothing of the sort. The 'noble savage' had been a simple charity case, worthy of pity certainly, but not philosophical enquiry.

Feral children have always aroused man's fascination. But, when Peter stumbled out of the forest in 1725, he encountered a world in intellectual ferment. Inspired by the Light of Reason and the Scientific Revolution, Europe's new secular intelligentsia was examining the world anew after centuries of obscurantism and superstition. An army of frustrated empiricists, they submitted everything and everyone to rational investigation. To them, Peter was a godsend: "the very Creature which the learned World have…pretended to wish for." They pamphleteered, polemicised and pontificated. But, like their subject, they were stumbling into the unknown, often lacking the words to pose the right questions and the knowledge to interpret their observations correctly. As a mute, Peter was unable to disabuse them of their wilder conjectures, and his mystery only deepened, fuelling the debate and spurring the theorists. In a sense, the philosophers of the Age of Reason had met their match. They were faced with a man who did not make sense. But for all their theories, it did not occur to them that he could not make sense - that there was no 'sense' to make. As Defoe had suggested, it is quite possible that they brought an Ideot upon the Stage, and made a great Something out of Nothing.

Whatever his ailments, Peter was not forgotten by the royal court. His keep was paid by the Crown for nearly 60 years, through three reigns, and, when he died, a brass tablet was erected to his memory at royal expense. But Peter was no more loquacious in death than he had been in life. He was given a prime spot in the graveyard at Northchurch, close to the south porch, and his rough-hewn stone, now shaded by an unruly dog rose, read simply: "Peter the Wild Boy - 1785".