A grass hopper cage.

A grass hopper cage

At Filippo Brunelleschi's death in 1446, the drum of the Cathedral of Santa Maria del Fiore wasn't completed. Inside the Opera del Duomo museum there are some models that correspond to the project Andrea del Sansovino, Antonio da Sangallo, Simone Pollaiolo made to finish the lower part of the dome Filippo Brunelleschi erected from 1420 to 1436. Works were commissioned to Baccio d'Agnolo in 1515 but he wasn't able to finish the marble decoration because Michelangelo, who had planned his project too, criticized Baccio so much he gave up. Michelangelo compared Baccio's architecture to a grass hopper cage: the structure was too slender to be situated at the base of the majestic work Brunelleschi built. According to Baccio's project, marble heads of lions, still visible inside the museum, reminded people the Florentine republic they belonged to and they even refered to a member of the Medici family Giovanni, Lorenzo il Magnifico' s son, who was elected Pope in 1513 with the name of Leo X. Two years later in 1515 he triumphally entered in Florence to celebrate its origins.
Michelangelo wanted a prominent frame without a gallery: an essemptial, simple architecture to accentuate the size of the dome!

The Cathedral of Santa Maria del Fiore with the uncompleted marble decoration for the drum