The Medici Chapels are two structures at the Basilica of San Lorenzo, Florence, Italy, dating from the 16th and 17th centuries, and built as extensions to Brunelleschi's 15th-century church, with the purpose of celebrating the Medici family, patrons of the church and Grand Dukes of Tuscany. The Sagrestia Nuova, was designed by Michelangelo. The larger Cappella dei Principi, though proposed in the 16th century, was not begun until the early 17th century, its design being a collaboration between the family and architects.