n the first half of the 15th cent. the sculptor Lorenzo Ghiberti embellished the Florentine baptistery with his splendid bronze doors, winning the commission in competition against another great sculptor and architect, Filippo Brunelleschi. Other sculptors, such as Desiderio da Settignano, Antonio Rossellino, and Bertoldo di Giovanni, carried the tradition established by Donatello through to Michelangelo, while the workshop of the Della Robbias during the 15th cent. produced a great quantity of superb terra-cotta relief sculptures. The Tuscan painters, including Fra Angelico and Fra Filippo Lippi, created works of exquisite color. Paolo Uccello and Andrea del Castagno contributed refinements to the understanding of the laws of perspective.