Costa was born in Rome, Italy. She and her sister, Anna Francesca, began their careers as singers and perhaps courtesans in Rome, where they received the patronage of families such as the Aldobrandini. In 1628, Costa moved to Florence, where she began her literary career. At the ducal court, she obtained the protection of Grand Duke
Ferdinando II de' Medici of Tuscany,
Vittoria della Rovere, and other members of the Medici family. She may have also married the court buffoon Bernardino Ricci, known as "Tedeschino" (as well as the "Cavalier of Pleasure"), to whom she dedicated a 1641 comedy entitled
The Buffoons. During this period, Costa also published several volumes of poetry, a drama, and a collection of love letters. Also printed under her name was a historical account of Ferdinando's 1627 voyage to Germany, but because Costa acknowledged that she received her information from a member of the ducal court, her detractors accused her of not having composed the work herself. In 1644, Costa left Florence and returned to Rome under the protection of Cardinal
Francesco Barberini, to whom she dedicated a sacred poem about the Roman
Saint Cecilia, the patron saint of music. Costa briefly left the city the following year in order to assume a post as a singer at the court of
Duchess Christine of Savoy. Costa would later portray the Turin court in a collection of poems dedicated to the duchess and published in 1647, at which time she had been invited to travel from Rome to Paris with the group of musicians of the composer Luigi Rossi, to sing in his opera , which was performed to glorify the court of the young
Louis XIV. Over the course of that year, under the patronage of
Cardinal Mazarin, she published a volume of poetry in honor of the king's mother and regent,
Anne of Austria, and the text for an equestrian ballet dedicated to the cardinal, as well as the volume for Christine of Savoy. Little is known about the latter part of her life. She was in Venice in August 1650 and from there she most likely traveled to Germany. In the dedication to the
dukes of Brunswick-Lüneburg of her play, *, (The Loves of the Moon Goddess), she claims that she lived for four years under a foreign sky. The play was published in Venice in 1654 on her way back to Rome. The last preserved document by Margherita is a letter written on May 4, 1657, to Mario Chigi, commander-in-chief of the papal armies and brother to Pope Alexander VII, imploring assistance. In this letter, she describes herself as a widow with two daughters. The date of her death is unknown. ==List of works==