Saint John the Baptist was considered the symbol, of moral rectitude and 'political correctness' on whom medieval Florence aspired to build its own economic fortunes and the good government of the Republic. The image of this saint, protector of the Calimala guild and patron of Florence, was even stamped on the city's currency, the florin.
Saint John the Baptist's birthday (June 24) has thus always been a popular holiday in Florence, which for the occasion organizes official celebrations. In the past, these ceremonies afforded an opportunity to display the power and grandeur of Florence.

Verrocchio (shop), Madonna with Saints. Detail: Saint Zenobius offers Florence to Mary. San Martino a Strada, Grassina.

The high point of the celebration is the solemn procession of the Cathedral clergy, which comes out of the main door of the Cathedral and enters the so-called "Gate of Paradise" in the Baptistery, following a route that connects these two buildings, making them, symbolically, a single sacred structure. In the past, the procession passed under an enormous awning, called 'heaven', which further underlined the meaning of this passage, emphasizing as it did the unitary nature of the space that links the octagon of the Baptistery to that of the Cathedral choir area.
In the past, all Florentine men of fifteen years and above brought a candle to the Baptistery on this occasion, and private houses, palaces and work premises were splendidly decked out. Piazza del Duomo too, between the Baptistery and the Cathedral, was covered by the above-mentioned 'heaven', a vast awning hung on taut cords, and on the eve of the feast a solemn procession was held. This custom was interrupted at the end of the fifteenth century due to a fire and a gusty wind storm. After first vesper of the Feast, the evening of June 23, there was the solemn offerting of votive gifts to the patron saint, especially candles.

Votive offerings being brought to the Baptistery on the Feast of Saint John (old print).

Part of these candles were lit during services in the Baptistery during the ensuing year, the rest were sold and the money then used to maintain and embellish the church. Candles were given not only by the elected city officials, but also by the Republic's magistracies, by the several guilds, by the lay and religious confraternities and by the 'outlands': the towns and territories conquered by the Florentines, who - at the moment of surrender - always imposed upon the conquered city or castle the obligation of offering a candle, a silk banner or other forms of tribute (including objects in silver or other materials, and even animals). During the ceremony, the enormous candles to be offered the patron saint were transported by hand or in carts, if - as often was the case - they were decorated with imposing figures in papier maché or painted wood.
This traditional offering of wax continues today, albeit in a simplified form: on the morning of June 24, a cortège leaves Palazzo Vecchio, composed of representatives of the City, the traffic police and members of the Society of Saint John the Baptist, with the mayor and other city authorities who, following the city's banner, walk to the Baptistery.
These official representatives are received in the Basilica of Saint John (as the Baptistery is formally known) by the Cathedral clergy, who at ten o'clock on the morning of the feast have gone to the Baptistery to sing Terce, part of the Divine Office honoring the patron saint.
In former times the celebrations continued for several days, during which the city's artisans set out their finest wares. There were two races in these days: on the eve of Saint John's Day, a coach race held in Piazza Santa Maria Novella, with four wooden carriages that, in different epochs, had different shapes, from Roman chariots to modern vehicles. On the afternoon of the Feast, then, there was the 'Palio of the Berbers' (called 'barberi'), a horse race that took its name from the race of animals used. According to the fourteenth-century chronicler Giovanni Villani, this race was a custom going all the back to 405 A.D., originally run in via Palazzuolo and then, from 1391 on, in Borgo Ognissanti and via della Vigna Nuova. Today in place of the horse race there is a football match in Renaissance costume, another traditional event that, in the past, was mounted in Carneval.

Night view of Florence with fireworks on the Feast of Saint John.

The evening of Saint John's Day, then, the City and the Society of Saint John the Baptist organize fireworks recalling the festive bonfires once lit to mark the summer solstice: a custom already current in ancient pagan times, which in Florence as elsewhere was preserved to mark the feast of the Precursor of Chrtist, John the Baptist.
Up to 1826, the fireworks were set off in Piazza della Signoria. Die to a fire there, they were moved to Ponte alla Carraia and finally, as still today, to Piazzale Michelangelo.