Contrary to what schoolchildren have been led to believe for more than three centuries, it might just be possible to put Humpty Dumpty together again. It would not even require all the king's horses and all the king's men to do it: an archaeologist, a large metal detector and an expert in 17th-century guns should do the trick.

The hapless Humpty, it appears, was not an egg (that notion did not take root until 1871, with the publication of Alice Through the Looking Glass and Sir John Tenniel's illustration of Humpty as an egg). The original Humpty Dumpty was really a large cannon, used by Royalist forces to defend besieged Colchester in 1648. Royalists under the command of Sir Charles Lucas defended the town against the encircling Parliamentarians for 11 weeks, largely thanks to “Humpty Dumpty”, the nickname for the cannon expertly operated by a Royalist gunner, “One-eyed” Thompson, and mounted on the church tower of St Mary-at-the-Walls.

Eventually, however, the Roundheads managed to score a direct hit on the tower, and Humpty (and Thompson) had a great fall. According to Albert Jack, in his new investigation of nursery rhymes, the shattered cannon “buried itself in deep marshland” outside the city walls. The reason all the king's men could not put the weapon back together again may have simply been that they could not find all the pieces buried in the Essex mud. In all probability the remains of Humpty are still there.

The rhyme was pure parliamentarian propaganda, a mocking ditty to show that the most effective weapon in the Royalist armoury had been neutralised, destroyed beyond repair. Putting Humpty together again, albeit 360 years late, would be a pleasing counter-coup for those of us still rooting for the Royalist cause (“Wrong but Romantic”).

One of the oddest aspects of nursery rhymes is their specificity. The names of the protagonists have been as perfectly preserved down the ages: Dr Foster, Jack Horner, Old Mother Hubbard have been handed down from child to child without alteration and often without curiosity. Yet all of these nursery rhyme characters can be traced into history, albeit tentatively.

The Grand Old Duke of York was probably James II, who marched his troops to Salisbury to do battle with William of Orange in 1688, and then marched them back again when he realised how many of his former allies had defected. Three problems: James II was not Duke of York, although he had been; he was 55, so not particularly old; and Salisbury Plain is pretty flat.

An alternative candidate is Prince Frederick, the unwarlike son of George III. The hill down which he marched may have been Mont Cassel, the hill near Tourcoing where the Prince's forces were soundly beaten by the French in 1794. On the other hand, the ten thousand men may refer to the workers toiling up and down hill at Frederick's mansion near Harrogate in order to build his (not strictly deserved) Temple of Victory on a nearby hillock.

The history behind nursery rhymes is not only highly specific, but often splendidly grim. Take “Mary, Mary, Quite Contrary”, an apparently simple tale of one girl's taste for elaborate horticulture that is really about torture. “Mary” may be Mary I, and the “garden” may be Steven Gardiner, her brutal Lord Chancellor. When the devoutly Roman Catholic Mary and Gardiner set about purging Protestants, imprisoned dissenters were tortured with a grisly array of implements: “cockleshells”, a device for crushing the genitals; “silver bells”, the nickname for thumbscrews; and “maids”, a sort of early guillotine. In this reading, Mary was not just contrary, but fabulously cruel. Her growing garden is, in fact, an expanding graveyard.

“Little Jack Horner” may have been steward to the abbot of Glastonbury, Richard Whiting. It is said that Whiting, attempting to protect his abbey from the dissolution, sent Horner to Henry VIII with the deeds to numerous properties, concealed beneath a pie crust, as a bribe. Horner, however, “pulled out a plum” - the deeds to Mells Manor House in Somerset. Whiting was hanged, drawn and quartered for his failure to obey the king without question; the descendants of Thomas Horner, who deny the legend, still live at Mells Manor House. “Bobby Shafto” was Robert Shafto, MP for County Durham, self-described as “bonny” to win votes and infamous for his ill-treatment of women.

Georgie Porgie may have been George Villiers, Duke of Buckingham, James I's favourite and possible lover, who was notorious for having affairs with women at court but “ran away” (ie, survived retaliation for the weeping ladies' husbands) because he enjoyed the King's protection. Miss Muffet, pioneer of arachnophobia, was the daughter of Dr Thomas Muffet, a 16th-century physician who studied the medical properties of insects, most notably spiders. Mother Hubbard was probably a joke at the expense of Cardinal Wolsey, who went to Rome (the cupboard) to get the dog (Henry VIII) a bone (a divorce), and failed.

Jack's book is a tribute to the English oral tradition, and a reminder of the riches beneath the surface of the playground rhyme: characters, jokes, events and stories, perfectly preserved and awaiting excavation from history, like the bits of Humpty Dumpty himself, waiting to be reassembled from the Colchester marsh.

Pop Goes the Weasel: The Secret Meanings of Nursery Rhymes by Albert Jack
Penguin, £12.99 Buy the book here

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