As the Romans said: Semel in anno licet insanire
‘once a year it is allowed to go crazy’
This Latin sentence became a proverb in the Middle Ages, and was often used to describe carnevale.
In the Middle Ages it was the period of craziness right before Lent, time of privation and prayer.
(Peter Brugel, Carnival versus Lent, Carnival is represented by people on the left, Lent is the ugly, skynny, old woman on the right)
In the XV century great feste carnascialesche (‘festivals’) were organized in bigger cities, with music, dance, and songs,
Lorenzo the Magnificent organized big celebrations with canti carnascialeschi (‘Carnival songs’), such as his Trionfo di Bacco e Arianna by Lorenzo the Magnificent, and trionfi, procession with big and extravagant floats, inspired to mythological figures and designed by the greatest artists
Huge carri allegorici (‘allegorical floats’) are still used in many carneval festivals all around Italy, such as Viareggio
(See also “I miss carnevale – 1 – 2” https://misshome.wordpress.com/2014/02/16/229-i-miss-carnevale-1/