Ignazio Danti
Ignazio Danti (April 1536 – October 19, 1586), born Pellegrino Rainaldi Danti, was an Italian
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

, mathematician
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, astronomer
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, and cosmographer
Cosmography is the science that maps the general features of the universe, describing both heaven and Earth...



Danti was born in Perugia
Perugia is the capital city of the region of Umbria in central Italy, near the River Tiber, and the capital of the province of Perugia. The city is located about north of Rome. It covers a high hilltop and part of the valleys around the area....

 to a family rich in artists and scientists. As a boy he learned the rudiments of painting
Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...

 and architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

 from his father Giulio, an architect and engineer who studied under Antonio da Sangallo
Antonio da Sangallo
Antonio da Sangallo may refer to:* Antonio da Sangallo the Elder , Florentine architect* Antonio da Sangallo the Younger , , Florentine architect and the Elder's nephew...

, and his aunt Teodora, who was said to have studied under the painter Perugino and also wrote a commentary on Euclid
Euclid , fl. 300 BC, also known as Euclid of Alexandria, was a Greek mathematician, often referred to as the "Father of Geometry". He was active in Alexandria during the reign of Ptolemy I...

. His older brother Vincenzo Danti would become one of the leading court sculptors of late-sixteenth-century Florence, while his younger brother Girolamo (1547–1580) would become a local Perugian painter of little fame.

Danti entered the Dominican Order
Dominican Order
The Order of Preachers , after the 15th century more commonly known as the Dominican Order or Dominicans, is a Catholic religious order founded by Saint Dominic and approved by Pope Honorius III on 22 December 1216 in France...

 on March 7, 1555, changing his baptismal name from Pellegrino to Ignazio. After completing his studies in philosophy and theology he gave some time to preaching, but soon devoted himself zealously to mathematics, astronomy, and geography.

In 1562, he requested a transfer from the Dominican compound in Perugia to the monastery of San Marco in Florence
Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....

. Soon after, he found work on the side tutoring the children of wealthy Florentines in mathematics and science. In September 1563, he was invited by Cosimo I, Duke of Tuscany to participate in his great cosmographical project, the Guardaroba in the Palazzo Vecchio
Palazzo Vecchio
The Palazzo Vecchio is the town hall of Florence, Italy. This massive, Romanesque, crenellated fortress-palace is among the most impressive town halls of Tuscany...

. Over the next dozen years, Danti would paint 30 maps of regions of the world (based largely upon published prints by Giacomo Gastaldi
Giacomo Gastaldi
Giacomo Gastaldi was an Italian cartographer of the 16th century. Gastaldi began his career as an engineer, serving the Venetian Republic in that capacity until the fourth decade of the sixteenth century...

, Abraham Ortelius
Abraham Ortelius
thumb|250px|Abraham Ortelius by [[Peter Paul Rubens]]Abraham Ortelius thumb|250px|Abraham Ortelius by [[Peter Paul Rubens]]Abraham Ortelius (Abraham Ortels) thumb|250px|Abraham Ortelius by [[Peter Paul Rubens]]Abraham Ortelius (Abraham Ortels) (April 14, 1527 – June 28,exile in England to take...

, Gerardus Mercator
Gerardus Mercator
thumb|right|200px|Gerardus MercatorGerardus Mercator was a cartographer, born in Rupelmonde in the Hapsburg County of Flanders, part of the Holy Roman Empire. He is remembered for the Mercator projection world map, which is named after him...

, and others) upon the cabinet doors of the Guardaroba. He would also work on many other significant scientific and cosmographic projects in Florence, including the large terrestrial globe
A globe is a three-dimensional scale model of Earth or other spheroid celestial body such as a planet, star, or moon...

 of the Guardaroba (1564–1568), and a number of brass scientific instruments (such as an astrolabe) today in the Institute and Museum of the History of Science
Institute and Museum of the History of Science
The Museo Galileo is based in Florence, Italy. It was founded in 1927 by the University of Florence...

 in Florence. Between 1567 and 1569, Pius V, who belonged to the Dominicans, is said to have commissioned Danti to furnish plans for the construction of a Dominican church and convent at Bosco Marengo
Bosco Marengo
Bosco Marengo is a town and comune in the Province of Alessandria in the Italian region Piedmont, located about 80 km southeast of Turin and about 12 km southeast of Alessandria....

 in Piedmont
Piedmont is one of the 20 regions of Italy. It has an area of 25,402 square kilometres and a population of about 4.4 million. The capital of Piedmont is Turin. The main local language is Piedmontese. Occitan is also spoken by a minority in the Occitan Valleys situated in the Provinces of...

; Danti acted mainly as an advisor. During his stay in Florence
Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....

, Danti taught mathematics and published over a dozen scientific treatises, mostly commentaries on ancient and medieval astronomy and mathematics or explanations of how to use scientific instruments.

For much of his time in Florence, Danti resided at the convent of Santa Maria Novella, and designed the quadrant
Quadrant (instrument)
A quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.-Types of quadrants:...

 (on the right) and the armillary sphere
Armillary sphere
An armillary sphere is a model of objects in the sky , consisting of a spherical framework of rings, centred on Earth, that represent lines of celestial longitude and latitude and other astronomically important features such as the ecliptic...

 (on the left) that appear on the end blind arches of the lower facade of the church in 1572 and 1574, respectively. He also designed a large-scale gnomon
The gnomon is the part of a sundial that casts the shadow. Gnomon is an ancient Greek word meaning "indicator", "one who discerns," or "that which reveals."It has come to be used for a variety of purposes in mathematics and other fields....

 for the church which would allow a thin beam of light to enter the church at noon each day through a hole just beneath the facade's rose window, although it probably was not completed by the time Danti left Florence.

There were also discussions between the Duke and Danti about building a canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

 to place Florence in communication with both the Mediterranean and the Adriatic. However, this grandiose plan never got underway before Cosimo's death in (1574). The following year Cosimo's son, Grand Duke Francesco I de' Medici, forced Danti to leave Florence (in late September 1575) on an uncertain morals charge. It is not known precisely why Francesco exiled Danti, but the Dominican had no trouble finding work or patrons anywhere else in Italy, although he never returned to Florence before his death.

After leaving Florence, Danti became professor of mathematics at the University of Bologna
University of Bologna
The Alma Mater Studiorum - University of Bologna is the oldest continually operating university in the world, the word 'universitas' being first used by this institution at its foundation. The true date of its founding is uncertain, but believed by most accounts to have been 1088...

. While occupying this chair he built a massive gnomon
The gnomon is the part of a sundial that casts the shadow. Gnomon is an ancient Greek word meaning "indicator", "one who discerns," or "that which reveals."It has come to be used for a variety of purposes in mathematics and other fields....

 in the Bolognese church of San Petronio, the meridian line
Meridian (geography)
A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...

 of which is still visible in the church's pavement. He also spent some time in Perugia, at the invitation of the governor, where he prepared maps of the Perugian republic.

On account of his mathematical attainments, Pope Gregory XIII
Pope Gregory XIII
Pope Gregory XIII , born Ugo Boncompagni, was Pope from 1572 to 1585. He is best known for commissioning and being the namesake for the Gregorian calendar, which remains the internationally-accepted civil calendar to this date.-Youth:He was born the son of Cristoforo Boncompagni and wife Angela...

 invited him to Rome, appointed him pontifical mathematician and made him a member of the commission for the reform of the calendar
Gregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

. He also placed him in charge of the painters whom the Pope had summoned to the Vatican
Vatican City
Vatican City , or Vatican City State, in Italian officially Stato della Città del Vaticano , which translates literally as State of the City of the Vatican, is a landlocked sovereign city-state whose territory consists of a walled enclave within the city of Rome, Italy. It has an area of...

 to continue the decoration of the palace, most notably to make a number of maps of the regions of modern Italy in the newly constructed Gallery of Maps along the Cortile del Belvedere
Cortile del Belvedere
The Cortile del Belvedere, the Belvedere courtyard, designed by Donato Bramante from 1506 onwards, was a major architectural work of the High Renaissance at the Vatican Palace in Rome; its concept and details reverberating in courtyard design, formalized piazzas and garden plans throughout Western...

. This remarkable project, begun in early 1580 and completed about 18 months later, maps the entirety of the Italian peninsula in 40 large-scale frescoes, each depicting a region as well as a perspective view of its most prominent city.

When the pontiff commissioned the architect Domenico Fontana
Domenico Fontana
Domenico Fontana was a Swiss-born Italian architect of the late Renaissance.-Biography:200px|thumb|Fountain of Moses in Rome....

 to repair the Claudian harbour it was Danti who furnished the necessary plans. While at Rome Danti published a translation of a portion of Euclid
Euclid , fl. 300 BC, also known as Euclid of Alexandria, was a Greek mathematician, often referred to as the "Father of Geometry". He was active in Alexandria during the reign of Ptolemy I...

 with annotations and wrote a life of the architect Jacopo Barozzi da Vignola, preparing also notes for the latter's work on perspective. In recognition of his labours Gregory, in 1583, made him Bishop of Alatri in the Campagna
Campagna is a small town and comune of the province of Salerno, in the Campania region of Southern Italy.-History:The town, located in a mountainous district, gradually lost importance in the 20th century...

. Danti showed himself a zealous pastor in his new office.

As bishop of Alatri, Danti convoked a diocesan synod
A synod historically is a council of a church, usually convened to decide an issue of doctrine, administration or application. In modern usage, the word often refers to the governing body of a particular church, whether its members are meeting or not...

, corrected many abuses, and showed great solicitude for the poor. Shortly before his death Pope Sixtus V
Pope Sixtus V
Pope Sixtus V , born Felice Peretti di Montalto, was Pope from 1585 to 1590.-Early life:The chronicler Andrija Zmajević states that Felice's family originated from modern-day Montenegro...

 summoned him to Rome to assist in the erection of the grand obelisk
Obelisks in Rome
The city of Rome harbours the most obelisks in the world. There are eight ancient Egyptian and five ancient Roman obelisks in Rome, together with a number of more modern obelisks; there was also formerly an ancient Ethiopian obelisk in Rome....

 in the piazza of the Vatican.

Besides the works already mentioned, Danti was the author of Trattato del'uso e della fabbrica dell'astrolabo con la giunta del planifero del Raja; Le Scienze matematiche ridotte in tavole, also a revised and annotated edition of La Sfera di Messer G. Sacrobosco tradotta da Pier Vincenzio Danti.

He died at Alatri, only three years into his service. After Danti's death, in 1588 Giovanni Antonio Magini
Giovanni Antonio Magini
Giovanni Antonio Magini was an Italian astronomer, astrologer, cartographer, and mathematician.-Life:...

 was chosen over Galileo to occupy the chair of mathematics at the University of Bologna.


  • Egnatio Danti, Les deux règles de la perspective pratique de Vignole, 1583, Pascal Dubourg Glatigny, Paris, 2003, ISBN 2-271-06105-9.
  • Ignazio Danti at the Catholic Encyclopedia
    Catholic Encyclopedia
    The Catholic Encyclopedia, also referred to as the Old Catholic Encyclopedia and the Original Catholic Encyclopedia, is an English-language encyclopedia published in the United States. The first volume appeared in March 1907 and the last three volumes appeared in 1912, followed by a master index...

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