Duke Cosimo I de' Medici was the first Grand Duke of Tuscany, ruling from 1537 until his death in 1574. He was born on June 12, 1519, and became Duke after the assassination of his cousin, Alessandro de' Medici. Cosimo was a significant patron of the arts and played a crucial role in the development of the Florentine Renaissance. Under his leadership, Tuscany flourished economically and culturally. Cosimo I strengthened the power of the Medici family and expanded their influence through strategic marriages and alliances. He also commissioned notable works from artists like Giambologna and Benvenuto Cellini, enhancing Florence's reputation as a center of art and culture.