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Lecture: Renaissance and Exploration (1350-1500)

The 15th and 16th centuries saw a change in thinking, influenced by the readings of classical and Arabic texts, and the flood of new ideas that always comes with expanding trade networks.

Optics and perspective

The same historian who gave us the explanation of the recovery of classical texts in Toledo, James Burke, can also tell us about the optics that came into Europe and changed the technology of painting and building.

The teaching of optics was based on 11th century sources that had been "recovered" from the Arab world.

Toscanelli would apply the knowledge to architecture, helping architects like Brunelleschi design buildings like Florence's Duomo, featuring the first full dome since the ancient world. The new science of optics also allowed a study of the geometric ways in which to see the world, which is what led to the perspective drawing and painting for which the Renaissance is so famous. And here's the more practical explanation of drawing from perspective, based on the work of Alberti, another great Renaissance architect:

Text here.

I think we can consider the word "perspective" in two different ways here. Perspective in drawing and art gave us some wonderful artworks, buildings, and even towns:

Masaccio's Trinty

Masaccio's Trinity (1428)

Santo Spirito

Brunelleschi, Santo Spirito, Florence (1434-71)

ideal city

Plan for the ideal city

But the revival of classical learning and Arab optics also created perspective in the sense of seeing things differently. When you can reproduce nature so accurately on a canvas, what's to say you can't control it further in real life? Certainly Renaissance towns were designed as much for social control as for military fortification and mathematical ratios. If we consider perspective as a technology, does the use of it change how people behave? The rational control of nature is, I think, a huge impetus to many technologies.

I also must say that I personally am very grateful to the study of Arab optics. Although spectacles (eyeglasses) were first known to be used in the 15th century, the convex lenses were only for far-sighted people. I am nearsighted, so would not have been able to have proper vision until the 16th century, when concave lenses were developed with the help of Arab knowledge.

Paracelsus, alchemist

Great Surgery"In all things there is a poison, and there is nothing without a poison. It depends only upon the dose whether a poison is poison or not…”

Into the history of technology, there is always some science. Given our understanding of chemistry as applied to medicine, Paracelsus becomes an important figure. Philippus Aureolus Theophrastus Bombastus von Hohenheim (1493-1541), known as Paracelsus, considered himself an alchemist. The son of a chemist and doctor, he attended multiple universities but found their teaching unsatisfactory. In a way, Paracelsus denied much of what the Renaissance was about. The recovery of classic texts had led to a move away from empiricism - in the Middle Ages there was much experimentation with various herbs and compounds. Paracelsus' understanding of substances led to the creation of laudanum, a distillation of opium that stopped pain, and other mineral-based medicines that in large doses were dangerous. Publication of his huge Great Surgery Book (left) in 1536 made him famous. He was the first to recommend mercury treatments for syphilis (more on this during the Enlightenment) and his treatments with antimony apparently cured Louis XIV years later. His ideas of "like cures like" may have provided the foundations for homeopathy in the 19th century, and he essentially invented chemotherapy. He was over 100 years ahead of his time in declaring as false Aristotle's claim that all metals derived from mercury and sulfur. Although he was discredited during his lifetime, and treated as a quack, and although a number of his cures that he considered magical were dubious, his contribution to both medicine and chemistry is now acknowledged.

I find it interesting that even when people were trying to call Paracelsus a "medical chemist" or the "Luther of medicine", he insisted that he was an alchemist. Alchemy has been considered by historians to be a precursor or fore-runner of modern chemistry. One of its central goals, the transmutation of lead and other base metals into gold, has been so discredited as to give the whole field a bad name. And yet not only Paracelsus, but later scientists like Newton, were alchemists.

There were many branches of alchemy, going back to medieval times. Paracelsus and Newton were into "practical alchemy", the active experimentation with substances, with the goal of creating a hypothesis. In other words, Renaissance alchemists were close to modern science in their methods. Prior to the late 16th century, alchemists had seen the supernatural as a cause of everything - they experimented with substances but believed the cause of the transformations they witnessed was magical or spiritual. As that approach was replaced by nature as a foundational cause, we approach the modern scientific method. In a sense, then, the "trial and error" methods so typical to technological development were a signal of maturation in the field of science.

The Caravel

I rarely put a single technology in its own section, but in this case I think it's warranted. By the 15th century, the Mediterranean had been dominated by small, lateen-sailed ships for centuries. Lateen sails are triangular, and when attached to lateen rigging, can be maneuvered to catch light winds and allow mariners to steer the ship precisely. This was important in the Mediterranean Sea, where a ship was not out of sight of land for long, and catching light winds was important for speed. When full rigs of lateen sails were tried on ships in northern Europe, they were too difficult to use. Rough seas and high winds made them difficult to manage.

For this reason, northern European ships had featured heavy hulls and square sails. At least since the Vikings, square-rigged ships had worked best in heavy seas.

The caravel combined the square sails for oceanic conditions with lateen sails for maneuvering, rigged on a medium-weight and sized hull. A caravel could maneuver out of a small port, sail along a coastline, cross a large body in heavy seas, and maneuver into shallow harbors abroad. Two things happened to make it the invention of the era.


First, in 1415, Prince Henry of Portugal (known as The Navigator) was looking for a way to cut out the Arab middlemen in the Sahara, and get west African trade goods (particularly gold and salt) directly from the source. At the time, the shape and size of Africa was not known beyond the Mediterranean coast and a little ways down the west coast. The map they had was just a 15th century version of Ptolemy's map:

ptolemy map

Notice how Africa just sort of dissolves into a southern land mass. By sailing down the west coast of Africa in a series of missions, Henry was able to map the coastline and track the currents and winds. His discoveries led to further explorations. In 1488, Bartholemeu Dias reached the Cape. By 1498, Portuguese mariner Vasco de Gama had rounded the tip of Africa and would be the first European to travel by sea to India. The caravel got him there.

The second event was that in 1453, the Ottoman Empire took the city of Constantinople. The Crusades, which had escalated in various more embarrassing forms from 1095 to 1404, had ended. The Ottoman Turks had been expanding from Asia minor since the 13th century. With their conquest they took over the trade routes of both Arab and Christian traders operating in the cross-over territory between Europe and Asia. The heart of that cross-over was the city of Constantinople (previously Byzantium when it was Greek, now Istanbul and Muslim).

What I was taught in school was that the Ottoman Turks forbade Christians from trading in the city, which cut off the supply of luxury goods to Europe. Actually, they began taxing Christian traders at the same rate as others, which increased the price of their goods.

By the 1480s, Genoese navigator Christopher Columbus had developed an idea for sailing west to get to Asia. The idea was the result of a great deal of study and some seriously faulty conclusions. At the time, there were arguments about the correct circumference calculations of the earth, anthropological discoveries of driftwood and bones washing up on the coast of Iberia, and the popularity of Marco Polo's book about his adventures to Asia. Due to his study of ancient texts and modern phenomenon, Columbus came to believe that the actual size of the earth is significantly smaller than it is, and that the Asian continent is much larger than it is. Thus he believed that the distance from Europe to Japan, directly to the West, was about 3,000 miles.

He introduced this idea to the king of Portugal, hoping for funding, and was turned down on the advice of the king's scholars. Columbus set out to get funding from other Renaissance princes, and was always turned down, because the court scholars had more accurate calculations of the size of the earth and of Asia. These scholars were convinced that if Columbus set off he would soon reach "the ends of the earth", the point (at about 3,000 miles) at which a ship runs out of food and water and cannot return. Funding finally was given by Queen Isabel of Spain, who had just united her country and was closing out the Reconquista kicking Muslims and Jews out of the country.

By the way, if you've heard stuff about Columbus believing the world was round when others said it was flat, and that he was right and everyone else was wrong, that's...well, wrong. Luckily, he did find land at about 3,000 miles, just as his crew was about to mutiny. And he did it in a caravel.

The Columbian Exchange: Labor

On a macro level, two global regions that had been isolated from each other collided with great force in the New World. Historian Alfred Crosby has called the long-term transfer of plants, animals and diseases between these regions the "Columbian Exchange". This map gives an idea:

Columbian Exhange

Hernando Cortes of Spain arrived with troops and conquered the Aztec empire in 1519. He had a lot of help - there were many tribes living under Aztec domination who joined them. But disease played a major role in the victory. European diseases (you can see the Mexicans suffering from smallpox in the lower left) killed off amazing numbers of Native Americans, because they had no immunity from long-term contact. This still happens today when an isolated tribe is discovered. Cortes considered their die-off as proof of God's support for the conquistadores. Many of those who didn't die ran away, using their knowledge of the terrain to escape. The result was that the Spanish, and later the Portugese in Brazil, didn't have enough labor to do the mining and farming necessary to make their new landholdings pay.

But in Africa, there was a source of labor. Since the 13th century, west African kingdoms had been expanding due to advanced political organization and domination of trans-Saharan trade routes. As these kingdoms expanded, they captured prisoners and traded them away. This provided both wealth for wars and got rid of populations that might rise up and cause trouble. These slaves were traded across the Sahara, and many had ended up in east Africa. Such slavery was not very abusive (despite the difficult trip) and slaves tended to be treated well in east Africa as part of the thriving economy there. High-class prisoners fetched higher values and were often able to pay their way to freedom for themselves or at least their children; lower-class prisoners were sold to do the work appropriate to their skills, be it silversmithing or farming. Muslim slave-traders dominated the trans-Saharan slave trade.

Europeans began arriving at west African ports and requesting slaves. It was handy for west African kingdoms, expanding inland and capturing prisoners of war, to trade these prisoners on the coast instead of to Muslim trans-Saharan traders. The character of the trade changed, and entrepreneurs on the west coast began journeying inland deliberately to capture people for what was becoming a trans-Atlantic slave trade.

The character of the trans-Atlantic slave trade was far more brutal than the trans-Saharan trade. Most interior Africans had never seen the ocean, much less a ship. They were piled in like animals, with no respect for class or language. Princes were chained next to peasants of different tribes, and all were treated as chattel. All would be put to mining or agricultural labor regardless of skill. Many threw themselves overboard, either not sure that the journey would ever end (it must have seemed like they had gone to hell) or unable to tolerate the treatment. But enough survived, and with their own disease immunity from Africa were able to reproduce. In Latin America, the children born to them were usually considered free, and intermarried despite various laws discouraging it. In North America, dominated by the 17th century by English and French, they became slaves in perpetuity, with their children inheriting their status.

Slavery, of course, was not new. Slavery was the foundation of much prosperity during the eras of classical Greece and Rome. Beginning in the 16th century, the Barbary slave trade captured Europeans and sold them in north Africa. The pirates who traded in slaves profited from weak Ottoman control of the north African coast, and a flood of Moorish refugees from the Reconquista in Spain (1492). African slaves, both black and white, had been an aspect of European life for centuries.

slave boy
Boy wearing slave collar, Dutch (17th century)
slave statue
Slave figures on the tomb of Doge Giovanni Pesaro, designed by Baldassare Longhena and sculpted by Melchior Barthel, Venice (17th century)

I consider slavery not only an inhumane practice, but a practical way of providing labor and a hindrance to technological development. With an easily importable work force, and economic structures cleverly set up for its perpetuation, there was little need for technological innovation in Latin America or in the colonial south of what would become the United States. I suppose one could note the instruments of slave punishment as technology, but in general the regions of innovation would be those that did not practice slavery, a very different situation from that of ancient Greece.


Leonardo pulleysLeonardo da Vinci gets his own section due to his pure understanding of technology as embodying practical use. In addition to being an expert painter, Leonardo designed many objects in his notebooks. Many of the inventions he drew were never built, or have been built by others as models. Some of the drawings were studies of mechanical possibility, such as the pulleys shown here to the right. He designed a helicopter, a diving suit, a glider, and all sorts of siege machinery. He created elaborate sets for theatrical performances, drew water-lifting devices and improved upon them, and was a true "Renaissance man".

Some of his drawings and inventions were used at the time, or came to be important technologies. One of the most significant is his design for a canal lock, still efficiently used on many canals today. We'll talk more about canals in the Enlightenment lecture.

Leonardo's Miter Lock:


This unit reaches beyond Europe, and the impact of its technologies reaches beyond the economy or the life of ordinary people. Was the caravel the cause of trans-Atlantic slavery? Was it necessary for Europeans to kill off so many people in the Americans? Does lack of scientific (or, in the case of Columbus, factual) information actually lead to more innovation? If you can design great things before anyone can build them, are you contributing to human knowledge? It is appropriate to the Renaissance itself that a small, practical technology can call into question larger issues of ethics, knowledge and science.



All text, lecture voice audio, and course design copyright Lisa M. Lane 1998-2018. Other materials used in this class may be subject to copyright protection, and are intended for educational and scholarly fair use under the Copyright Act of 1976 and the TEACH Act of 2002.