Eight years ago, leafing through a bibliography of 16th-century music prints (like you do), my eye was caught by the title of a motet: “Salve sponsa Dei.” “Bride of Christ,” I thought. “Must be for nuns!”

It was one of 23 anonymous motets published together in 1543, so I did what any self-respecting nunologist would do, and ordered a reproduction of the book. As I put the motets into a usable edition for modern singers, I found they were unlike any other 16th-century music I’d ever seen. They were dense, intense and sometimes startlingly dissonant.

Facebook Twitter Pinterest Musicologist and conductor Laurie Stras: ‘Suddenly I understood why this music made bishops so queasy’

The music – for five equal voices (of unspecified sex) – is astonishingly beautiful and yet strange, radical even. These works had lain unsung and unloved for almost four centuries, mostly because they were anonymous. These days, anonymity suggests that whoever created the book, music, painting or whatever was not important enough, or the product is not good enough, for anyone to care who made it. But in the 16th century, anonymity was also an important way for members of the nobility to disguise their participation in commercial ventures that were considered beneath them (which is why Gesualdo, a prince, published his madrigals anonymously).

But Virginia Woolf was right when she said: “Anonymous was a woman.” Respectable ladies were also not supposed to enter the marketplace, so if their work did appear in print it would often do so without a name, or – as we know from later centuries – under a pseudonym. If circumstances were different, we might still think that the novels of George Eliot and Currer Bell were written by men. We will never know how much 16th-century music published anonymously, or by composers for whom we can find no biographical detail, was by women.

These motets were published decades before any other printed music that is proven to be for convents, but I felt certain they were written for nuns by a fellow nun: a nun princess called Suor Leonora d’Este. You may not recognise the name, but you may have heard of her infamous mother, Lucrezia Borgia?

Leonora (1515-75) was the only surviving daughter of Lucrezia Borgia and her third husband, Duke Alfonso d’Este of Ferrara. Lucrezia died when Leonora was only four, of complications after the birth of what was possibly her 10th child. Leonora was raised at the convent of Corpus Domini in Ferrara, where her mother was buried, because there was no woman of her rank to raise her at court. Aged eight, she decided to enter the convent permanently, and became abbess when she was 18. This may seem young for a woman to be in charge, but her mother was appointed Governor of Spoleto at only 19 – perhaps she had inherited her mother’s administrative ability. She may have chosen to become a nun rather than be a marriageable bargaining chip for her father, and so she could do the things she most wanted to do – play and study music – without the distraction of childbearing or politics. She would have learned from her mother’s experience what a mixed blessing it was to be the daughter of a powerful family.

Like the rest of her family, Leonora was highly educated and deeply interested in music, but, unusually for a woman, she was allowed to develop that interest into real expertise that was noted and admired by the most respected musicians of her time. But her musical abilities were all the more unusual, and potentially controversial, because she was a nun. Nuns’ music was highly valued by the populace: travel writers throughout the 16th century would recommend musical convents to potential visitors to Venice and Ferrara, in particular.

But the church’s hierarchy was divided on the issue. Some thought nuns singing polyphony were doing God’s work, and called their choirs “celestial sirens”, as the beautiful sound of their voices drew more people to worship. But others were of the opinion that they were doing the devil’s work, because music made the sisters susceptible to vanity. In 1539, the Bishop of Verona banned all polyphony outright in every convent under his jurisdiction, saying nuns should use the “mental attention used to understand notation and the rules of music” to concentrate on the liturgy instead.

Hearing these motets, I really understood for the first time why the bishops were so queasy about nuns’ singing. Even those not used to Renaissance music can tell these motets are really unusual; they are sensuous and unexpectedly moving. Often they seem closer to the music of our own times’ John Tavener than Palestrina: five voices weaving hypnotically around each other, pulling the listener in. The constant echoing between the parts seem like whispers or faint but insistent memories of a melody and, before you know it, you are ensnared by an earworm before the work has even finished.

The most impressive piece in the book is a motet for Easter Sunday, Haec dies. Its final “Alleluia” sounds like an extended peal of bells, with all the tonal clashes and random rhythms you might hear if you were standing in the middle of Ferrara with all the churches’ belltowers going off at once. Bells were forbidden during Holy Week, and Alleluias are forbidden during the whole of Lent, but they joyously returned to the nuns on Easter morning. On paper, it looks impossible that it was written in the 16th century, but I found it copied into a 17th-century manuscript from a Bohemian monastery – and the monks clearly loved it so much they added the text for Christmas morning to it, so they could sing it twice a year.

The motets’ texts reflect aspects that are particularly personal to nuns: one piece has a long and ravishing section beseeching the Virgin Mary to pray for “the consecrated feminine sex”. Another, a prayer to St Clare, is based entirely on a melody constructed from the sol-fa syllables (do-re-mi, etc) whose vowel sounds match those of the words of the prayer. Clare was the founder of Suor Leonora’s convent order, and the sol-fa syllables would have been the way Leonora taught her young novices to sing – so it seems everyone in the convent could join in the music for the founder’s feast. Other clues that led me to Leonora include several aspects – melodies, contrapuntal practices – that link the music to works from the Este chapel, some of which was private and known only to her family, as well as the strong concentration in the collection of music for their patron saint, Clare.

Ultimately there is no conclusive proof that the music is by Leonora, and there may never be, but in the end, the identity of the composer is less important than the music itself: sophisticated, modern, challenging and expressive, it deserves to be heard and appreciated alongside the greatest works of the 16th century.

