The tiny island of Inchkeith, which lies around 3 miles north of Edinburgh in middle of Scotland’s Firth of Forth, has had a long and turbulent history. In the 12th century, the island was first used as a stop-off for boats and ferries sailing from Edinburgh to Fife. Two centuries later, Inchkeith’s position made it strategically useful during the Scottish Wars of Independence, and it was repeatedly attacked by invading English troops during the lengthy Anglo-Scottish Wars. In the 15th century, it was used to quarantine the sick during an outbreak of the “contagious sickness callit the grandgor” (syphilis) in nearby Edinburgh, and again during an outbreak of the plague 100 years later. But the most unusual event in the island’s history may have taken place in 1493, when the Scottish king James IV chose to use the island as the location of a bizarre and cruel language deprivation experiment.

Of all Scotland’s kings, James IV is remembered as a true Renaissance man: well-educated and naturally inquisitive, he was fond of history, art, poetry, and literature, and interested in medical advancement and scientific enlightenment. During his reign he became patron to a number of notable Scots writers and makars (bards), studied dentistry and surgery, licensed the first printworks in Scotland, and funded several court alchemists and apothecaries to carry out their experiments under his supervision. One of James’s best known alchemists, John Damian, is even supposed to have used the king’s funds to construct a set of man-sized chicken-feather wings, which he used to launch himself from the parapets of Stirling Castle, claiming that he would be able to fly to France; needless to say, he failed, and was reportedly left with a broken leg after plummeting into a dung heap several stories below.

Of all the king’s intellectual interests, however, his love of language was perhaps the most significant. James is reputed to have been the last Scottish monarch to have spoken Scots Gaelic as well as English, but he was also fluent in Latin, French, German, Italian, Flemish, and Spanish, which the Spanish envoy to Great Britain, Pedro de Ayala, informed King Ferdinand of Spain that he spoke “as well as the Marquis, though he pronounces it more distinctly.”

It was James’s love of languages, combined with his natural inquisitiveness and empiricism, that apparently led him to conceive of his peculiar experiment: In 1493, the king ordered two newborn babies to be sent to live on the isolated island of Inchkeith to be raised by a deaf mute woman. His aim was to see what language (if any) the children acquired, because with no other linguistic input, he believed that this language, whatever it might be, must surely be the innate, God-given language of mankind.

Language deprivation experiments precisely like this one have a lengthy history—one of the earliest is recorded in the works of the Greek historian Herodotus, who wrote that, in the 7th century BCE, the Egyptian pharaoh Psamtik I sent two infants to live with a shepherd in one of the most isolated parts of his kingdom, on the condition that they never be spoken to. According to Herodotus, the children repeatedly babbled the word bekòs, an ancient Phrygian word meaning “bread,” leading Psamtik to believe (albeit mistakenly) that Phrygia rather than Egypt was mankind’s oldest civilization.

Similar experiments were reportedly carried out by the Holy Roman Emperor Frederick II (“But he laboured in vain, for the children could not live without clappings of the hands, and gestures, and gladness of countenance, and blandishments,” according to one account), and the 16th century Mughal Indian Emperor Akbar, who found that children raised in isolation remained mute even as they grew older.

But whether or not King James IV genuinely carried out his own deprivation experiment on Inchkeith is open to some speculation, and it’s certainly possible that his love of languages—alongside tales of similar experiments being carried out elsewhere—merely sparked a tall tale that has since refused to die. Nevertheless, the 16th century Scottish historian Robert Lindsay of Pitscottie included James’s experiment in his Historie and Chronicles of Scotland, compiled almost 100 years later. As he explains:

The king also caused [to] take one deaf woman, and put her in Inchkeith, and give her two bairns with her, and furnish her in all necessary things pertaining to their nourishment, desiring hereby to know what languages they had when they came to the age of perfect speech. Some say they could speak Hebrew, but for my part I know not but from [other people’s] reports.

Did the children really learn to speak fluent Hebrew? You can make your own mind up on that one—but as the author Sir Walter Scott later commented, “It is more likely they would scream like their dumb nurse, or bleat like the goats and sheep on the island.”