Eleanor of Toledo (Italian: Eleonora di Toledo (11 January 1519 ā 17 December 1562), born DoƱa Leonor Ćlvarez de Toledo y Osorio, was a Spanish noblewoman who was the wife of Cosimo I de' Medici and the Duchess of Florence.
Although Eleanor is often referred to as the Grand Duchess of Tuscany, she predeceased the creation of the Grand Duchy of Tuscany.
She is credited with being the first modern first lady, or consort.
She served as regent of Florence during the absence of her spouse.
Eleonora di Toledo, ritratto della scuola di Agnolo Bronzino, possibly on the occasion of her death, in 1562. Based on an earlier portrait by Bronzino.