Juana Inés de la Cruz de Asbaje y Ramirez was born in San Miguel Nepantla (now called Nepantla de Sor Juana Inés de la Cruz in her honor) near Mexico City. She was the illegitimate child of a Spanish Captain, Pedro Manuel de Asbaje, and a Criollo woman, Isabel Ramírez. Her father, according to all accounts, was absent from her life. She was baptized 2 December 1651 and described on the Baptismal rolls as “a daughter of the Church”. She was raised in Amecameca, where her maternal grandfather owned a hacienda. She was a devoutly religious child who often hid in the hacienda chapel to read her grandfather’s books from the adjoining library, something forbidden to girls. She learned how to read and write at the age of three. By age five, she reportedly could do accounts. At age eight, she composed a poem on the Eucharist.By adolescence, she had mastered Greek logic, and at age thirteen she was teaching Latin to young children. She also learned the Aztec language of Nahuatl, and wrote some short poems in that language.

In 1664, aged 16, she was sent to live in Mexico City. She asked her mother’s permission to disguise herself as a male student so that she could enter the university. Not being allowed to do this, she continued her studies privately. She came under the tutelage of the Vicereine Leonor Carreto, wife of the Viceroy Antonio Sebastián de Toledo. The viceroy (whom Appletons’ Cyclopædia of American Biography names as the Marquis de Mancera), wishing to test the learning and intelligence of this 17 year old, invited several theologians, jurists, philosophers, and poets to a meeting, during which she had to answer, unprepared, many questions, and explain several difficult points on various scientific and literary subjects. The manner in which she acquitted herself astonished all present, and greatly increased her reputation. Her literary accomplishments garnered her fame throughout New Spain. She was much admired in the viceregal court, and declined several proposals of marriage. In 1667, she entered the Convent of the Discalced Carmelites of St. Joseph as a postulant. In 1669, she entered the Convent of the Order of St. Jérôme.

In response to critics of her writing, Juana wrote a letter, Respuesta a Sor Filotea (Reply to Sister Filotea), in which she defended women’s right to education. In response, the Archbishop of Mexico joined other high-ranking officials in condemning Sor Juana’s “waywardness”. By 1693, Sor Juana seemingly ceased writing rather than risk official censure. However, there is no undisputed evidence of her renouncing devotion to letters, though there are documents showing her agreeing to undergo penance. Her name is affixed to such a document in 1694, but given her deep natural lyricism, the tone of these supposed hand-written penitentials is in rhetorical and autocratic Church formulae; one is signed “Yo, la peor de todas” (“I, the worst of all the women”) She is said to have sold all her books,then an extensive library of over 4,000 volumes, and her musical and scientific instruments as well. Only a few writings have survived, which are known as the Complete Works.