The sundial on Ponte Vecchio

Sundials are the most ancient instruments for measuring time. Before the invention of mechanical clocks mounted on towers, in the early years of the 14th century, "sun clocks" were the only instruments used to indicate the public time. But since the precision of mechanical clocks was poor, sundials continued to coexist with tower clocks in city squares up to the middle of the 17th century. The sundial on Ponte Vecchio dates from the 13th century, and is a simple vertical dial indicating the canonical hours, that is, the moments of the day dedicated by the Catholic Church to common prayer: the first hour, Laud (at sunrise), when Matins was recited, the third, Tierce (at 9:00 o'clock), the sixth, Sext (at midday), the ninth, None (at 3:00 o'clock), and the twelfth (at sunset), when Vespers was chanted. Divided in this way, the hours of the day differed in length according to the season.

Brunelleschi's clock

Goldsmith, sculptor, architect and engineer, Filippo Brunelleschi (1377-1446) was also an excellent clockmaker, who derived the secrets of his remarkable construction machines from that very art. "Having engaged with pleasure in the past in making some clocks and alarm clocks", writes his biographer, "in which there are many different generations of springs, which are multiplied by great numbers of ingenious devices … this was extremely helpful to him in being able to imagine various machines used for hauling and hoisting and drawing.” The only clock of his known to us today was built in 1445 for the tower of the Palazzo dei Vicari in Scarperia. It is composed of two separate mechanical parts: the time part, formed of three wheels, and the bell-tolling part, composed of three wheels and a sprocket wheel to regulate the speed of the stroke. In one of the many restoration initiatives the escapement, of the rod type with "foliot" governor, was replaced by a pendulum. The weights were reset by means of four levers actuated manually by a “temperer”. The original dial, no longer existing today, was square in shape, with the hours circle divided into 24 sections in the "Italian hour" style.

Paolo Uccello's clock

The first public clock in the city of Florence was installed on the tower of Palazzo Vecchio on March 25, 1353, the work of Niccolò di Bernardo. A little less than a century later, a grandson of his, Angelo Niccolai degli Orologi, was commissioned to construct the mechanical clock of Santa Maria del Fiore, installed on the cathedral's inner façade in 1443. The dial was painted in fresco by Paolo Uccello (1397-1475), inscribing in a square a circle divided into 24 hours running counter-clockwise, according to a conventional representation of the time, emulating the movement of the gnomon's shadow on a vertical sundial. The hours are given in the so-called "Italian style", which marked the duration of the day starting from sunset. They are indicated by an elliptical star with one ray longer than the others, an element recurrently used by the artist in his paintings to depict the comet of the Nativity. This is probably an allusion to Christ, “light of the world”, as is further confirmed by the presence of the four Evangelists portrayed in the false oculi at the corners of the great square.

Lorenzo Della Volpaia's clock

Architect, goldsmith, mathematician, but above all clockmaker, Lorenzo Della Volpaia (1446-1512) was the founder of that Florentine family of clockmakers and scientific instrument-makers among whose distinguished members were his sons Camillo (1484-1560), Benvenuto (1486-1532), Eufrosino (late 15th – 16th century) and his grandson Girolamo (c. 1530-1614). As a clockmaker, he won honour and fame with the construction of the planetary clock commissioned by Lorenzo the Magnificent as a gift for the King of Hungary, Mattias Corvino, but subsequently donated to the Signoria to be placed in the Hall of the Clock (today's Hall of Lilies) in Palazzo Vecchio. The clock was restored in 1560 by Girolamo della Volpaia and placed in the Guardaroba, which Cosimo I had commissioned Egnazio Danti (1536-1586) to arrange as a ‘cosmography room’. Dismantled and destroyed in the 17th century, the clock is known today through a reconstruction by Alberto Gorla and Giuseppe Brusa now in the Florence Museum of the History of Science.