Maria Gaetana Agnesi  16 May 1718 – 9 January 1799 was an Italian mathematician, philosopher, theologian and humanitarian.

Maria Gaetana Agnesi was born in Milan, to a wealthy and literate family the third of 21 children. Her father Pietro Agnesi, a University of Bologna mathematics professor, her mother was the daughter of a prosperous silk manufacturer. Maria’s father supported her learning but gave priority to his sons. She soon outstripped her brothers and she was recognised as a child prodigy before she was 10 years old. She could speak both Italian and French at five years of age and by her eleventh birthday, she had added Greek, Hebrew, Spanish, German, and Latin to her arsenal of knowledge. She was often referred to as the “Seven-Tongued Orator”.

When she was nine years old, she composed and delivered an hour-long speech in Latin to some of the most distinguished intellectuals of the day; and the subject was, of course, a women’s right to be educated.

At the age of 12, she was found to be suffering from some undefined malaise. Her ill health was automatically attributed to her excessive studying and her doctors prescribed vigorous dancing and horseback riding as a remedy. This treatment did not work; she began to experience extreme convulsions, after which she was encouraged to be moderate in all her pursuits.

But there was no stopping Gaetana, by the age of fourteen she was studying ballistics and geometry and a year later her father began to regularly include her in his gatherings which included some of the most learned men in Bologna. Here she would read papers on the most abstruse philosophical questions of the day. Records of these meetings are given in Charles de Brosses’ Lettres sur l’Italie and in the Propositiones Philosophicae, which her father published in 1738.

In 1739 two Burgundian gentlemen were passing through Milan on their ‘Grand Tour’. They were Charles De Brosses, conseiller, at the parliament of Dijon and its future president Germain Ann Loppin de Montmort, conseiller at the parliament of Bourgogne, and a mathematician. While touring the churches and libraries of Milan in July 1739 they met Count Belloni and were invited to attend a salon or conversazione at the Agnesi Palazzo. The evening was that of the 16th of July, tired and thirsty the two men arrived at the main gate of the Palazzo Agnesi. The Palazzo’s exterior was elegant but plain. They were greeted by footmen dress in grey livery and taken to the first-floor apartment via a small drawing room adorned with vivid landscape paintings. They were then led through a larger room decorated with tapestries of gold and silver where a portrait of Holy Roman Emperor Charles VI and his consort for Elizabeth Christine gazed down on them. Finally, they arrived at a room with a harpsichord and decorated in crimson damask, where they were invited to sit in an audience of about 20 notable guests and served with glasses of iced water. Gaetana was there with her sister, the composer, and musician, Maria Theresa, and the conversation began when Count Belloni rose and asked Gaetana a question in Latin concerning the nature of tides. Gaetana began the discourse in the form an academic disputation putting forward ideas then dismissing them. An hour later Brosses was invited to ask a question, he decided to question her on the subject of the nature of the soul and the body and on the nature of light and colours. Then Loppin asked a question about the nature of circles and curves. When the discussion was over they were served fruit flavoured ices and Theresa played the harpsichord to entertain the guests.

In 1740, aged twenty-two, Gaetana began a period of studies with Father Ramiro Rampinelli, professor of physics and mathematics in Milan in the monastery of Olivetani of San Vittore. Rampinelli was an Olivetan monk and chair of mathematics and physics at ‘ University of Pavia. With Rampinelli Maria started to study other notable mathematicians and both differential and integral calculus.

Gaetana’s main contribution to the world of mathematics was the formula for a curve called ‘versiera’ a term derived from Latin vertere, to turn, but is also an abbreviation of Italian avversiera, female devil. Some wit in England once translated it as ‘witch’, and the silly pun is still preserved in most English textbooks. This curve appeared in the writings of Fermat (Oeuvres, I, 279–280; III, 233–234) and in the work of other prominent mathematicians. The name ‘versiera’ is from Guido Grandi (Quadratura circuli et hyperbolae, Pisa, 1703) and is a type 63 in Newton’s classification. Its principal use today is in astronomy and to show the distribution of energy in objects such as ocean waves.

With the help of fellow mathematician and astronomer Jacopo Riccati, she drafted her first book, Institutions Analytical for use by the Italian Youth which was published in Italian in 1748 and dedicated to Empress Maria Teresa. The book was well received and was translated into French in 1755 and English in 1801. In 1750, she replaced her father in teaching mathematics at ‘ University of Bologna and when he died in 1752, Pope Benedict XIV gave her a special dispensation to hold the rank of Professor but she did not take it up. Instead, she dedicated herself to charitable works; she opened a small hospital and worked there herself nursing the poor at the end of their lives.

Her religious inclinations led her to study theology in the second half of her life. She was a devout Catholic and wrote extensively on the marriage between intellectual pursuit and mystical contemplation, most notably in her essay Il Cielo Mistico (The Mystic Heaven). She saw the rational contemplation of God as a complement to prayer and contemplation.

Gaetana was the first woman to write a book on mathematics and the first to teach mathematics at a university. She was the first female professor of mathematics too although she never took up the post. Her lasting legacy is her wave, known as The Witch of Agnesi. Other honours included the dedication of one of the largest craters on the planet Venus; a metal model of a versiera is embedded in the square outside the town hall of the city of Varedo as a tribute to their most famous inhabitant and the house she lived in until she died in 1799 is now a music academy there. As a tribute to her genius several Italian cities have dedicated a street in her honour and in Merate ( LC ) there is a high school specialising in science and languages named after her.

Sources: Wikipedia and The World of Maria Gaetana Agnesi, Mathematician of God By Massimo Mazzotti, JHU Press, 2012

Julia Herdman writes historical fiction that puts women to the fore. Her latest book Sinclair, Tales of Tooley Street Vol. 1. is  Available on Amazon 

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