1502 – Florence, Italy

‘In the Renaissance science was reinvented’

Image of the VITRUVIAN MAN


Leonardo is celebrated as the Renaissance artist who created the masterpieces ‘The Last Supper’ (1495-97) and ‘The Mona Lisa’ (1503-06). Much of his time was spent in scientific enquiry, although most of his work remained unpublished and largely forgotten centuries after his death. The genius of his designs so far outstripped contemporary technology that they were rendered literally inconceivable.

The range of his studies included astronomy, geography, palaeontology, geology, botany, zoölogy, hydrodynamics, optics, aerodynamics and anatomy. In the latter field he undertook a number of human dissections, largely on stolen corpses, to make detailed sketches of the body. He also dissected bears, cows, frogs, monkeys and birds to compare their anatomy with that of humans.

It is perhaps in his study of muscles where Leonardo’s blend of artistry and scientific analysis is best seen. In order to display the layers of the body, he developed the drawing technique of cross-sections and illustrated three-dimensional arrays of muscles and organs from different perspectives.

Leonardo’s superlative skill in illustration and his obsession with accuracy made his anatomical drawings the finest the world had ever seen. One of Leonardo’s special interests was the eye and he was fascinated by how the eye and brain worked together. He was probably the first anatomist to see how the optic nerve leaves the back of the eye and connects to the brain. He was probably the first, too, to realise how nerves link the brain to muscles. There had been no such idea in GALEN’s anatomy.

Possibly the most important contribution Leonardo made to science was the method of his enquiry, introducing a rational, systematic approach to the study of nature after a thousand years of superstition. He would begin by setting himself straightforward scientific queries such as ‘how does a bird fly?’ He would observe his subject in its natural environment, make notes on its behaviour, then repeat the observation over and over to ensure accuracy, before making sketches and ultimately drawing conclusions. In many instances he would directly apply the results of his enquiries into nature to designs for inventions for human use.

Self portrait of LEONARDO DA VINCI


He wrote ‘Things of the mind left untested by the senses are useless’. This methodical approach to science marks a significant stepping-stone from the DARK AGES to the modern era.

1469 Leonardo apprenticed to the studio of Andrea Verrocchio in Florence

1482 -1499 Leonardo’s work for Ludovico Siorza, the Duke of Milan, included designs for weaponry such as catapults and missiles.
Pictor et iggeniarius ducalis ( painter and engineer of the Duke )’.
Work on architecture, military and hydraulic engineering, flying machines and anatomy.

1502 Returns to Florence to work for Pope Alexander VI’s son, Cesare Borgia, as his military engineer and architect.

1503 Begins to paint the ‘Mona Lisa’.

1505-07 Wrote about the flight of birds and filled his notebooks with ideas for flying machines, including a helicopter and a parachute. In drawing machines he was keen to show how individual components worked.

1508 Studies anatomy in Milan.

1509 Draws maps and geological surveys of Lombardy and Lake Isea.

1516 Journeys to France on invitation of Francis I.

1519 April 23 – Dies in Clos-Luce, near Amboise, France.

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PARACELSUS (1493-1541)

Europe – early sixteenth century

‘Added salt to the mercury/sulfur diad, making a trinity to match the holy trinity’

picture of philippus aureolus theophrastus_paracelsus


Elaborating his writings with occult mystery, Theophrastus von Hohenheim renamed himself Paracelsus and helped to reform medicine by making it chemical.
Many of his ideas were erroneous and his writings were deliberately obscure; he insisted that the ‘doctrine of signatures’ could reveal efficacious drugs for different organs. Proclaiming that specific therapies could counter a particular disease was a radically different approach to the Aristotelian attempts to rebalance an individual’s internal humors.

Paracelsus extended the ‘fundamental qualities’ of the four Aristotelian elements by adding a third ‘hydrostatic principle’ to the diad of J’BIR IHBIN AYAM – saying the material manifestation of the ancient elements ( ‘…everything that lies in the four elements’ ) may be reduced to mercury, sulfur and salt.

The first distillate of an organic substance would be the thin, volatile ‘mercury’, which acted in favour of youth and life while next came the ‘sulfur’, acting in favour of growth and increase. Finally, the dry mass left behind was the ‘salt’. The concept of these three principles was considered a slight advance upon that of the four elements.

These are not the same things as we recognize today, nor elements in their own right; the first two were components of metals, salt was a principle common to all living things.

The Royal physicians of Elizabeth I of England and Henry IV of France assimilated and adapted Paracelsus’s ideas and although his theories lost credibility, his chemical remedies entered mainstream medicine.

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1543 – Poland

‘The Sun is at the centre of the solar system, fixed and immobile, and planets orbit around it in perfect circles in the following order: Mercury, Venus, Earth with its moon, Mars, Jupiter and Saturn’

diagram of the heliocentric Copernican system

The heliocentric Copernican system

The Copernican system defied the dogma that the Earth stood still at the centre of the universe – a concept that dated back to ARISTOTLE, which had been given observational legitimacy by PTOLEMY and authority by Christendom – and set forth a new theory of a Sun centered universe. Why would God create a hugely complicated system of equants, epicycles and eccentrics, as Ptolemy had used to explain planetary motion around the Earth, when it would be much more simple and graceful to have them all revolving around the Sun?

“Eight hundred years before Copernicus, a model of the solar system was advanced with the Earth as a planet orbiting the Sun along with other planets”
A few centuries later this idea fell into disfavour with the early Christian Church, which placed mankind at the centre of the universe in a geo-centric model. The alternative teaching would be deemed heresy punishable by death and it would not be until the seventeenth century that the work of GALILEO, KEPLER and NEWTON gave credence to the ideas revitalized by Copernicus in 1543.

Not only did Copernicus place the Sun at the centre of the solar system, but he also gave detailed accounts of the motions of Earth, the Moon and those planets that were known at that time. Between 1510 and 1514 he drafted Commentariolus, his initial exposition of the theory. In order to have credence, the idea required that the Earth itself be not fixed in position. He said that the Earth revolves on its own axis once every twenty-four hours, which accounts for day and night and explains the apparent movement of the stars and Sun across the sky. Copernicus suggested in Commentariolus that the time taken for each planet to complete its cycle through the night sky might increase the further it is from the Sun.

Mercury’s cycle takes 88 days, which makes it the nearest planet to the Sun. Venus takes 225 days, Earth 1 year, Mars 1.9 years, Jupiter 12 years and Saturn 30 years. Thus Copernicus was able to work out the truth and attempted to establish the order of the planets.

He did not publish his findings because they were thought to contravene the teachings of the Catholic Church. Religious leaders of his time were against him. Martin Luther (founder of the Lutheran Church in Germany) denounced him as ‘a new astrologer…. the fool’ who wanted ‘to overturn the entire science of astronomy’. His book De Revolutionibus Orbium Coelestium (On the revolution of the celestial spheres) was published at the very end of his life, and a copy placed on his deathbed. Thus the greatest astronomer of his time died without seeing his book in print – the book as influential as Newton’s Principia and Darwin’s ‘On The Origin of Species’.

Portrait of Copernicus

The text was rejected by many academics; partially because the author had undermined the simplicity of his initial ideas by clinging to the Aristotelian belief that planetary motion took place in perfect circles. This meant Copernicus had been forced to introduce his own system of epicycles and other complex motions to fit in with observational evidence, thereby producing as equally complicated an explanation as the geocentric one he had initially rejected for its lack of simplicity.

It was not until Johannes Kepler offered the solution that the planets move in an elliptical, not circular, motion in 1609 that the simplicity that Copernicus had been seeking was offered and the rest of the model could be vindicated.

In fact, it was not until 1616 that the Church banned the text Copernicus eventually published for its ‘blasphemous’ content, although that sanction remained in place until 1835.

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1543 – Padua, Italy

‘In spite of his premature death, Vesalius left behind a revolutionary legacy to anatomy students’

Portrait of Vesalius &copy:


By his reasoned, critical approach to GALEN he broke the reverence ascribed to the former master and created a model for independent, rational investigation in the development of medical science.


In 1543, Vesalius published ‘De Humani Corporis Fabrica Libri Septem‘ (The Seven Books on the Structure of the Human Body). Book One reveals Vesalius’s understanding of the importance of the skeleton. Book Two is about muscles; Book Three – Veins and Arteries; Book Four – The Nervous System. Book Five concerns the Main Body Organs; Book Six – The Heart & Lungs; Book Seven – The Brain.


At 42cm tall and 28cm wide with over 700 densely packed pages, it was impressive in size alone. It contained 200 illustrations, was the first definitive work on human anatomy actually based on the results of methodical dissections of humans and was the most accurate work on the subject ever written. Galen himself had never dissected a human body as this had been forbidden by Roman religious laws.

Anatomical Study Illustration from De Humani Corporis Fabrica 1543Anatomical Study Illustration from De Humani Corporis Fabrica 1543

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TYCHO BRAHE (1546-1601)

1577 – Denmark

‘The heavens are changeable, and the comets move through space. The Earth is the centre of the Universe, and round it rotates the Moon and the Sun. The planets orbit the Sun’


Up to now it had been believed that planets were carried on ‘heavenly spheres’ that fit tightly around each other.

Brahe dissented from the Copernican doctrine and accepted the dogma that the Earth stood still. His real contribution to astronomy was as an observer, rather than as a theorist. He accurately measured the position of 777 stars, a remarkable achievement considering it was done without a telescope. He also measured the movement of planets, but was unable to determine their orbits.

His observations paved the way for the discoveries of his assistant, Kepler. After Brahe’s death Kepler inherited Brahe’s vast accumulation of data on planetary observations.

portrait of tycho brahe


Brahe’s observation of the supernova of 1572 and the comet of 1577 convinced him that the Universe was not unchangeable as was believed by philosophers of his time. The notion of celestial spheres was not possible because comets moved through these spheres. But he still placed the Earth at the centre of the Universe. His contemporary, the Italian philosopher GIORDANO BRUNO (1548-1600), believed in the Sun centered Copernican system and for these heretical beliefs was burned at the stake.

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