Marguerite was born in 1492, two years before François. Raised in enforced seclusion by their mother after their father died and François became the heir presumptive to the throne, Marguerite shared in the expansive humanist education Louise provided for her son. Tutored by the finest of scholars, she learned to read Latin and to speak Italian fluently. Her love of letters and learning remained constant throughout her life. As princess and queen, she supported writers and poets and animated literary circles at court. She herself wrote poems and plays and authored the Heptaméron, a collection of tales and debates about love modeled after Boccacio's Decameron. The Heptaméron, one of the earliest works of prose fiction written in French, first appeared in print in 1558, although it circulated in manuscript form well before that.
Much of Marguerite's work is religious in nature, as she was a strong supporter of the burgeoning Protestant faith. Although she herself never broke with the Catholic church, she supported the early evangelicals Guillaume Briçonnet and Jacques Lefèvre d'Etaples, humanists who called for reform from within the church itself. She protected writers such as Clément Marot and Bonaventure Des Périers when they got into trouble with religious authorities. She invited Guillaume Farel to preach at her court in Nérac and corresponded with Jean Calvin. Several of her own works came under censure by the Sorbonne for their unorthodox religious content, although her proximity to the king protected her from punishment. It was primarily through her influence that François remained tolerant of the new faith for as long as he did.
When Marguerite was eleven, her mother had tried to marry her to Henry VIII, but was refused. Marguerite's one true love, Gaston de Foix, died a hero in the Italian wars in 1512. At seventeen, Marguerite was married to Charles d'Alençon in a political match; after he died a few years later, she wed Henri II, King of Navarre. She bore Henri a daughter, Jeanne d'Albret, in 1528; her only son, born when she was 38, died in infancy. Sister to one king, Marguerite became the grandmother of another: her daughter Jeanne's son Henri became King of France (as Henri IV) in 1589.
In addition to her learning and openness to new ideas, Marguerite de Navarre was known for her great charity and kindness. In her later years, she devoted herself to good works and provided education for poor children in her kingdom. Born two years before her beloved brother, she died two years after he did, in 1549. This "pearl among pearls" was indeed one of the most influential women of the Renaissance. Her poems, plays and prose allow us to witness the evolution of evangelical thought in France and provides us a vivid example of the curious mingling of the earthly with the divine that characterizes Renaissance culture.
If you'd like to read some of Marguerite's tales, you can find an English translation of the Heptaméron here.