Gerardus Mercator

Gerardus Mercator, married (to Barbara Schellkens) with six children, moves in 1552 at age forty to the Duchy of Cleves to become a mapmaker and lecturer at the University of Duisburg.

Once here, he becomes a well-known figure, and assists the duke in establishing a grammar school by helping to design its curriculum.

After establishing a cartographic workshop and engaging his own engravers, he returns to his main interest.

He publishes a superb six-panel map of Europe in 1554.

London-born John Dee had attended the Chelmsford Catholic School from 1535 (now King Edward VI Grammar School (Chelmsford)), then—from November 1542 to 1546—St. John's College, Cambridge.

His great abilities as an alchemist, astrologer, and mathematician recognized, he had been made made a founding fellow of Trinity College, where the clever stage effects he produced for a production of Aristophanes' Peace had procured him the reputation of being a magician that will cling to him through life.

He had traveled in the late 1540s and early 1550s in Europe, studying at Leuven (1548) and Brussels and lecturing in Paris on Euclid.

He had studied with Gemma Frisius and become a close friend of the cartographer Gerardus Mercator, returning to England with an important collection of mathematical and astronomical instruments.

He had met Gerolamo Cardano in London in 1552: during their acquaintance they investigated a perpetual motion machine as well as a gem purported to have magical properties.

Rector at Upton-upon-Severn from 1553, Dee had been offered a readership in mathematics at Oxford in 1554, which he declined; he was occupied with writing and perhaps hoping for a better position at court.

Dee becomes in 1555 a member of the Worshipful Company of Mercers, as his father had, through the company's system of patrimony.

He is arrested this same year and charged with "calculating" for having cast horoscopes of Queen Mary and Princess Elizabeth; the charges are expanded to treason against Mary.

Dee appears in the Star Chamber and exonerates himself, but is turned over to the Catholic Bishop Bonner for religious examination.

His strong and lifelong penchant for secrecy perhaps worsening matters, this entire episode is only the most dramatic in a series of attacks and slanders that are to dog Dee throughout his life.

Clearing his name yet again, he soon becomes a close associate of Bonner.

Gerardus Mercator produces a map of the British Isles in 1564.

His famous navigation chart of the same year introduces the map projection bearing his name, with its parallels and meridians at right angles.

Mercator first uses his cylindrical projection on his world map of 1569.

He begins work on his great Atlas, in which he seeks to describe the creation and history of the world.

Ignazio Danti, born in Perugia to a family rich in artists and scientists, had learned the rudiments of painting and architecture from his father Giulio, an architect and engineer who had studied under Antonio da Sangallo, and his aunt Teodora, who was said to have studied under the painter Perugino and also wrote a commentary on Euclid.

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

Danti had entered the Dominican Order 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 had soon devoted himself zealously to mathematics, astronomy, and geography.

He had requested a transfer in 1562 from the Dominican compound in Perugia to the monastery of San Marco in Florence, soon after finding work on the side tutoring the children of wealthy Florentines in mathematics and science.

He had been invited in September 1563 by Cosimo I, Duke of Tuscany, to participate in his great cosmographical project, the Guardaroba in the Palazzo Vecchio.

Over the past dozen years, Danti has painted thirty maps of regions of the world (based largely upon published prints by Giacomo Gastaldi, Abraham Ortelius, Gerardus Mercator, and others) upon the cabinet doors of the Guardaroba.

He has also worked on many other significant scientific and cosmographic projects in Florence, including the large terrestrial globe of the Guardaroba (1564–1568), and a number of brass scientific instruments (such as an astrolabe) today in the Museo Di Storia Della Scienza in Florence.

Pius V, who belonged to the Dominicans, is said to have commissioned Danti between 1567 and 1569 to furnish plans for the construction of a Dominican church and convent at Bosco Marengo in Piedmont; Danti has acted mainly as an advisor.

During his stay in Florence, Danti has 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.

Danti has resided for much of his time in Florence at the convent of Santa Maria Novella, and had designed the quadrant (on the right) and the armillary sphere (on the left) that appear on the end blind arches of the lower facade of the church in 1572 and 1574, respectively.

He has also designed a large-scale gnomon for the church which will 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 is not completed by the time Danti leaves Florence.

There had also been discussions between the Duke and Danti about building a canal 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, forces Danti to leave Florence in late September 1575 on an uncertain morals charge.

It is not known precisely why Francesco has exiled Danti, but the Dominican is to have no trouble finding work or patrons anywhere else in Italy, although he will never return to Florence.