William Shakespeare had a secret sibling: long-lost document thought to have been written by playwright’s father but actually written by his sister Joan, study claims

Say the words ‘Shakespeare’s sister’ and you might think of the Irish pop duo from the 1980s, or a famous song by The Smiths.

In fact, most people are unaware that the great English playwright ever had a brother or sister.

But according to a University of Bristol academic, there is ‘no doubt’ she existed – and a long-lost document suggests she was also interested in writing.

Joan Shakespeare, who was five years younger than her brother William, wrote a religious document called the ‘Spiritual Testament’, research has found.

Until now, scholars thought the document was written by William’s father, John, but this misconception may be due to a transcription error and gender bias at the time.

The new research was carried out by Professor Matthew Steggle, from the University of Bristol’s Department of English, who says Joan is ‘almost unknown’ today.

‘There are no illustrations of Joan, just seven pieces of paper from her life on which her name is written, but there is no doubt that she existed,’ he told MailOnline.

“That’s about the standard for a paper trail for a not-too-wealthy woman of the 17th century.”

Joan Shakespeare was five years younger than her brother and in the later years of his life was his only significant living relative apart from his wife and daughters.

Joan lived all her life in the family home on Henley Street in Stratford-upon-Avon – known as William’s birthplace and now a major tourist attraction.

It is believed that she married a penniless merchant, after which her name was changed to Joan Hart.

She had four children and outlived both her husband and her famous sibling by thirty years, living quietly in part of the Shakespeare family’s old home.

Professor Steggle’s research focused on a crucial document known as the ‘Spiritual Testament’, which was found by a mason in the rafters of the Shakespeare house around 1770, but is now sadly lost.

‘It was last recorded in 1790 and was returned to its owner, who ran a pub in Stratford,’ Professor Steggle told MailOnline.

“I imagine it was put on display in his cafe and thrown away during a renovation or something.”

A transcription has been made of the document, printed in 1790, which the academic says is ‘closest to the original’.

In the 1790 transcription the author calls himself “John” in the first person, but Professor Steggle thinks this was a mistake.

“What we have is this transcription from 1790, where the name is transcribed as ‘John’ every time,” he said.

‘But it is a common mistake for people transcribing seventeenth-century documents to misinterpret the name ‘Joan’ as ‘John’.

‘In seventeenth-century handwriting they can look very similar, especially if you expect to see a man’s name there.’

Spiritual Testament is actually an English translation of a religious Italian text, ‘The Last Will and Testament of the Soul’.

In it, the writer promises to die a good Catholic death – which was controversial at the time because Catholicism was strongly frowned upon.

For example, one excerpt reads: “I will willingly accept death in whatever way it comes to me, and conform my will to the will of God; accepting this as satisfaction for my sins and thanking his divine majesty for the life he has given me.”

For centuries, the assumption that the author was Shakespeare’s father John fueled the belief that he was a Catholic.

To investigate, Professor Steggle used Google Books and other Internet archives to track down early editions of that text in Italian and six other languages, many editions of which have survived in only one copy and are scattered throughout the libraries of Europe.

According to Professor Steggle, the Spiritual Testament could not have been written by John because ‘The Last Will and Testament of the Soul’ was published in 1613, more than ten years after John’s death in 1601.

This proved that it was several years after John Shakespeare’s death, and so the author of the English translation found in Shakespeare’s house was in fact the only other possible Shakespeare – Joan – who lived from 1569 to 1646.

In his research, Professor Steggle argues that Joan adapted ‘The Last Will and Testament of the Soul’ to create the Spiritual Testament in the 1730s.

The research shows not only that Joan, not John, was the closest Catholic, but also that she, like her brother, was interested in writing.

Ultimately, historical gender bias may have played a role in obscuring the truth about who adapted this copy of the Spiritual Testament in Shakespeare’s household.

“Until now, no one has noticed that this was hers because no one thought a document like this could be from a woman,” Professor Steggle said.

“Shakespeare’s Sister” is also the name of a famous essay by Virginia Woolf, about how Joan could never hope to become a writer or have her writings survived.

“She has become a kind of symbol for all the lost voices of early modern women,” Professor Steggle added.

“Hundreds of thousands of words from her brother survive, and so far none of any description from her.”

The research, published in the journal Shakespeare quarterlyis part of Professor Steggle’s work on an upcoming biography of William Shakespeare.