The astronomical clock of Mantua

The astronomical clock in Mantua is a precious and ancient work of wisdom.

By Mantova Museo Urbano Diffuso

Astronomical clockMantova Museo Urbano Diffuso

Astronomical clock

Piazza Erbe today is in the center of Mantua, but once upon a time it belonged to the very first suburb of the virgilian city, whose oldest nucleus was located where Piazza Sordello is located. Its beauty is largely due to buildings raised or restored over the centuries, from the Middle Ages to the Renaissance and beyond. In particular, the Tower of the Clock was built in the year 1473 as a completion of the Palace of the Reason, where politics and justice were administered in the era before the Gonzaga family took power over Mantua. The author of the tower is Luca Fancelli, the Tuscan of Settignano who decided so much about the view of Mantua, carrying out the indications of Leon Battista Alberti.

However, the imposing statue of the Immaculate Virgin Mary, the source of the Moon, the balcony and the upper crown, were added later. The XV century appearance of the tower and the square probably can be derived from an ornate wooden artwork of the Cathedral of Cremona, created by Giacomo Maria da Piadena called il Platina. Here stands out the stylized figure of the astronomical clock, invention of the genius of Bartolomeo Manfredi. He was first a mathematician, John’s of the Clock son.

Astronomical clockMantova Museo Urbano Diffuso

Astronomical clocks had spread mainly in Northern Europe already during the XIV century. In Italy, the oldest is certainly located in Padua, which today overlooks Piazza dei Signori but which came, at least as a conception, from the lost Reggia Carrarese. The astronomical clock of Mantua is the second built in Italy in order of time, and the first one that today we can see in the site for which it was conceived. Luckily the construction of the Clock is documented by a letter from Manfredi and illustrated by a text printed by Pietro Adamo de 'Micheli.

So we have a precious testimony of the original purposes of the mechanism, of its way of pointing out the astrological time and also of the astronomical culture that in the Renaissance was so influent.
Manfredi's clock has at least eight effects. Here we list them synthetically. 

First Effect: let the people know how many hours have passed since sunset.Second effect: to show the zodiacal sign in which the sun is.
Third Effect: to show if the moon is new or full.
Fourth effect: to make possible the calculation of the Ascendant; this is an astrological technical detail of the highest importance to infer the influence of the stars at an exact moment.

Astronomical clockMantova Museo Urbano Diffuso

Fifth Effect: to describe which one between the seven known celestial bodies (Sun, Mercury, Venus, Moon, Mars, Jupiter, Saturn) reigns at some time.Sixth Effect: Knowing the particular hours of the mantuans, each one marked with a sound; there were in fact six different bell sounds dividing the day.Seventh effect: to know how many hours have passed after midday.
Eighth effect: to understand how long the daytime part and the night part of a certain day were.

Letter from Bartolomeo Manfredi to the Marquis Ludovico II GonzagaMantova Museo Urbano Diffuso

The astronomer Bartolomeo Manfredi wrote this letter on the 29th June 1473 to inform the Marquis Ludovico Gonzaga that he had completed the astronomical clock. After that he describes the features of his invention: not only it marks the hour, but also tells the people the useful days for the various daily work and the critical days in which various infirmities are possible.
“It is now possible to put it on the tower, to let it come to the pleasure of Illustrious Lord of mine, to whom I swear eternal loyalty."
This letter is now preserved in the State Archives of Mantua, which we thank for granting us the image.

Astronomical clockMantova Museo Urbano Diffuso

The dial of the clock, restored on 25th October 1989, thanks to Alberto Gorla's mastery, can be described starting from its center.
The figure shining in the middle is, according to Pietro Adamo de 'Micheli, the mythological mother of Diana and Apollo, or of the Moon and the Sun. He says it because he claims that her name, Latona, was written above her, also if its attributes are typical of Diana.

Astronomical clockMantova Museo Urbano Diffuso

The crescent moon is on the top of her head, and on the side she has a gentle fawn. Next to the left hand is indicated the moon phase; from the same hand there is a golden ray that indicates a sign of the Zodiac, where the Moon is; the right hand, armed with a falcon, indicates the day of the lunar cycle.
Latona is surrounded by a first record of twenty-nine lunar days, in Arabic numerals, and a second record of twelve zodiac signs. Each sign is then characterized by six shields, which divide it 5 degrees to 5 degrees.

A hand marked by the Sun symbol indicates the zodiac sign of the day.
We can see also twenty-four painted bands, twelve white and twelve black, corresponding to the daytime and night time.
In the middle there is a blue semicircle, fixed to the zodiac from the first degree of Libra to the last of the Pisces, to represent the celestial equator. Finally, the exterior part of the dial is distinguished by the twenty-four hours of the day, painted with latin letters, which naturally correspond to vulgar hours, indicated by another appropriate hand.

Drawing of the dialMantova Museo Urbano Diffuso

In December 1473, in Mantua was printed a little book in which the mantuan Pietro Adamo de 'Micheli described the functions, the purpose and the symbolism of the astronomical clock. He has been called a singular character indeed. He studied law in Ferrara but was also largely self-taught. As an author, we know only this text, which offers him the opportunity to demonstrate his lyric quality and his undoubted scientific and technical knowledge.
Pietro Adamo was also the first Mantua publisher, leading to the printing in 1472 a Tractatus Maleficiorum and later the Decameron.

It was certainly facilitated by a distant relationship with the Gonzaga family, which allowed him to have a good favor for his activities.
"Here Piero Adamo depicts all the effects & demonstration of this admirable & singular work called clock."
The treatise on the clock is further illustrated by two embossed china designs, which probably derive from another mutilated little book. The most interesting is the quadrant, in which stands the central goddess, accompanied by the fawn and the crescent moon.

Astronomical clockMantova Museo Urbano Diffuso

We have not described in detail the complicated functioning of the clock, which is based on several independent movements, all governed by the inner mechanism of the tower. Instead, it is important to emphasize that even today, citizens and visitors of Mantua look curiously at the zodiacal hands and symbols that show how complex is the passage of time and how many myths and beliefs dragged on with it.

Clock zodiac dialMantova Museo Urbano Diffuso

Clock and zodiac

Inside the tower, we can admire the original metal discs of the clock. We can see the larger one, the zodiacal, and the one in which appears the figures corresponding to the division on lunar days.
The disk on which the zodiac signs are located in is itself an artwork. 

They are engraved with great skill by an unknown master, who has probably put all possible care in illustrating the seasonal principles in which the time of the year was divided. From the distant past, through Babylon and Greece, faith in the signs comes to the Middle Ages and the Renaissance, remaining in the midst of heated debates, basically intact.

Clock zodiac dial, detail of the ScorpionMantova Museo Urbano Diffuso

"Scorpio is a fixed, northern, frigid, humid, dormant, fleeting and feminine sign, and dominates over the shameful parts of the man and his infirmity, and his planet is Mars. When the Moon is in Scorpio, it is bad to start a chimney on the ground or ascend mountains or threes."
This description of the Scorpion sign contained in the Pietro Adamo’s Declaration makes us understand how much the zodiacal characteristics were important to the Renaissance man in his actions, despite of the Christian faith. So we can also understand how these images, the far-off heirs of ancient gods, were shaken in copper with utmost care. Each of them, in fact, represents a beautiful sculpture that can be admired in the halls of the Time Museum housed within the Clock Tower.

clock zodiac dial, detail of the SagittariusMantova Museo Urbano Diffuso

"Sagittarius is an hybrid, oriental, hot and dry, choleric, masculine, and dominates above the thighs and above the superfluous or missing members, as would be the sixth finger that a man could have in his hand against nature, or over a hand of four and above the infirmities of those, and above the blindness and the guilty, and above the beasts' impediments, and above the spine of the back, and his planet Lord is Jupiter. "
Here Pietro Adamo, in describing the emblem of Sagittarius, the last autumnal sign, usually depicted by a centaur who is about to shoot an arrow (but here instead we can see an equally armed snake-like triton creature) talks about the characteristics on which the sign dominates. Dominance is a central concept in astrology, and involves the protection of the zodiacal part on particular human activities, on parts of the body or even, as in this case, on malformations of the person. Each sign is then connected to one of the planets so far known in the solar system, or to the Sun itself or the Moon.

Clock MechanismMantova Museo Urbano Diffuso

How the clock works

In 1989, thanks to the Municipality of Mantua, the ancient clock was restored by the precious work of Alberto Gorla, the watchmaker of Rivarolo Mantovano. The mechanism was rebuilt and made fully operational. Gorla himself describes it to us as a complex with a length of 2.80 meters, a width of 2.40 and a height of 1.90.
Following his own words: "The machinery is made up of two trains: the time train and the ringer train, that are placed one next to the other and also near to the astronomical machine."
The watchmaker also says that the driving force is made up of weights that give to the clock an autonomy of 48 hours.

But the charging system is automatic. If the watch stops, you must recharge it and record it manually with a manual maneuver that records the exact time of day, month, zodiac, night length, moon phases, and the lunar age expressed in lunar days.
Thus, since 1989 the ancient artifact is again efficient and marks in front of the eyes of the mantovans and visitors the time of the day and the astral time, bringing us almost perfectly at the time of the Renaissance.

Clock MechanismMantova Museo Urbano Diffuso

The heart of the mechanism are the gears, which allow him to live. A work of great wisdom and a precious restoration indeed.

Clock gearsMantova Museo Urbano Diffuso

Inside the tower, in the Museum of Time, some ancient gears of the clock mechanism are shown. In particular here we can see two toothed wheels of the XVIII century.

Remnant fresco inside the TowerMantova Museo Urbano Diffuso

On the tower, above the clock dial, there is a marble canopy. Under the shed there were twelve frescoed finishes that long ago featured portraits of men ducts in the arts of Quadrivium: geometry, arithmetic, music and astrology. One of these rounds was replaced with the metallic moon sphere that we can see today. All of them are unfortunately very ruined and most of them are totally unreadable, even vanished. The four best preserved are up, just below the shed.
Probably of a similar age is the piece of the fresco that appears inside the tower, in the room where the mechanism is engraved on the dial. He portrays a severely-looking woman, beautiful and blonde. It's hard to figure out whether it is a historical character or, more likely, some symbolic representation of the time span.
Between the woman and the mechanism also survives another fragment of painting, a sketch that perhaps should be the sinopia for a subsequent fresco: here we see traces of vegetation and a large arm raised, almost like a clock hand.

Mantua Clock dialMantova Museo Urbano Diffuso

The clock face

Here we can see the image of the ancient clock, as it appears in a reprint from 1547 Pietro Adamo de Micheli’s work, titled "Declaration of the Clockwork of Mantua", kept at the Virgilian Municipal Library and illustrated by the printer Giacomo Ruffinelli.
In addition to presenting a detailed description of the dial, the printing shows us that the whole process of time seems to be supported by Hercules, who here takes on almost the task of Atlas, giving the burden of raising with his sturdy arms the sky of the zodiac, the figures that indicate the flow of hours and the goddess 

Diana from which the indication of the same.
On the sides of the mythical character we can see also two men dressed in the Oriental way, differently identified: certainly two wise men, one of whom in all likelihood is Ptolemy.
The work of Pietro Adamo is accompanied by a sonnet kept in the National Library of Florence, which reminds the vanity of human gestures in the face of the inexorable proceeding of divine will. Here are some of his verses:"But God laughs, and there he divides
honors, treasures and kingdoms,
and cause to fail our wills and projects.
Cesar kept the whole world in one hand,
and then Cassio and Bruto broke all his dreams
and all the efforts and the thoughts where vain. "

Credits: Story

Ideato e promosso da / Founded and promoted by:
Mattia Palazzi (Sindaco del Comune di Mantova)
con Lorenza Baroncelli (Assessore alla rigenerazione urbana e del territorio, marketing urbano, progetti e relazioni internazionali del Comune di Mantova)

Coordinamento scientifico / Scientific coordinator:
Sebastiano Sali

Curatore testi e immagini / Superintendent texts and images:
Giovanni Pasetti

Foto di / Photo by:
Gian Maria Pontiroli

Redazione / Editor:
Fabrizio Foresio

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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