About History: Amazing early inventions II

Roman concrete

By rights the Pantheon in Rome should not exist, except that it does after more than 2,000 years. Given the technology of the time it should not have been possible for Roman engineers to have constructed such a perfect concrete dome spanning 43 metres, pierced by its great oculus or “eye”. Still standing two millennia after its concrete was first poured, it remains the largest unreinforced dome in the world. It is a structure that has resisted earthquakes, fires, the sack of Rome and centuries of use. Visitors to the Pantheon today can marvel at this example of architectural brilliance but few probably acknowledge the extraordinary role of Roman concrete.

Concrete itself was not a Roman discovery as there is evidence that Nabatean builders were using an early form of it as far back as 6,500 BC. The Roman innovation was adding pozzolana, a volcanic ash sourced from the Bay of Naples to a traditional lime and water mix. The additive created a durable hydraulic concrete with the unique property of setting underwater and the ability of growing stronger over time. The material is even able to “self-heal” when exposed to water.

Concrete was the foundation of an architectural revolution that meant Roman engineers were not bound by the limitations of cut stone. Its use led to impressive basilicas, amphitheatres such as the Colosseum, and monumental harbours and warehouses like those built in Ostia. Concrete allowed the construction of multi-floored insulae (apartment blocks) that housed tens of thousands of Rome’s inhabitants. It enabled the building of bridges across Europe’s rivers some of which are still in use today, and the vast network of aqueducts that kept the Empire’s citizens supplied with fresh water. 

Writing

Homo sapiens have walked this planet for some 300,000 years. In all those millennia humanity relied on the spoken word or pictograms to communicate and record thoughts, beliefs, ideas and histories. Such was the case until around 3200 BC when the first writing system emerged in ancient Sumer in Mesopotamia. From there the concept of writing spread over the world via a process German ethnologist and archaeologist Leo Frobenius called “cultural diffusion” [1]. The discovery of ancient Mesoamerican scripts, far distant from Middle Eastern sources, proved writing systems had been invented independently in at least five different times and places: Mesopotamia as mentioned, Egypt around 3250 BC, Micronesia in the 1800s BC, Shang Dynasty China around 1300 BC, and in Mesoamerica after 900 BC. Of these original writing systems, Egyptian and Sumerian are the oldest known (Regulski, 2016).

These new writing systems did not supplant oral traditions but did dramatically extend the reach of communication. Groups could record and disseminate their histories, knowledge, traditions, and laws which became fundamental to how communities understood themselves in time and place. According to associate professor of history at Duke University, Adriane Lentz-Smith: “Writing made societies easier to administrate over distance. For better or worse, it allowed the development of bureaucracy” (Lentz-Smith, 2026, 42). Moreover, the advent of the next amazing invention meant the written word could be circulated faster and further than ever before. Whole nations and global interests could now be governed from a single location.

Printing innovation

The sharing of written knowledge exploded with the invention of the printing press in AD 1440 by German goldsmith, Johannes Gutenberg. His design was modelled on the helical screw press used by ancient Roman wine and olive oil producers to crush grapes and olives. Moreover, Gutenberg’s printing press also used innovative moveable cast metal type, known as “sorts” [2], to represent individual letters or characters known in typesetting as glyphs [3]. When typesetting compositors combine sorts into lines of type to make up a “forme” secured in a “chase” from which a page is printed. Using moveable type sets meant Gutenberg presses could print up to 3,600 pages per day compared to 40 by hand-printing and a few by hand-copying.

A printing revolution ensued spreading from Gutenberg’s Mainz workshop to more than 200 European cities. Famously, it was William Caxton (born in Kent, England c. 1422; died in London in 1491) who first introduced the printing press to London. He had learned the art of printing in Köln (Cologne) where he lived from 1470 to the end of 1472. He set up a press in Brugge some time in 1474 where “The Recuyell of the Historyes of Troye”, the first book printed in English, was published in 1475. Caxton’s translation from the French of “The Game and Playe of the Chesse” (in which chess is treated as an allegory of life) was published a year later. He went on to print two or three other works in French while in Brugge, but toward the end of 1476 Caxton returned to England. He established his press at Westminster and devoted himself to writing and printing. The first dateable book printed in English, “Dictes and Sayenges of the Phylosophers”, appeared on November 18th, 1477.

Coinciding with a sharp rise in learning and literacy among the middle-classes, by AD 1500 more than 20 million books had been produced by the new printing presses. As demand for books increased, so did the printers’ output, which rose to an estimated 150-200 million copies during the 16th-century. Quite simply, traditional mediæval scribes could not have kept up with such a voracious demand.

Reforming practices

Arguably the greatest impact of the printing press was the democratisation of knowledge. Even more people had access to ideas and information previously denied them. Yet, while fuelling worthwhile debate, dissent also followed. German priest, theologian, author, hymnwriter, professor, and former Augustinian friar, Martin Luther (10 November 1483 – 18 February 1546) was the seminal figure of the Protestant Reformation. Ordained to the priesthood in 1507, Luther came to reject various teachings and practices of the Roman Catholic Church, in particular the view on indulgences [4] and papal authority. Luther initiated an international debate on these in works such as his “Ninety-five Theses” authored in 1517. From 1518 to 1520, some 300,000 copies of his tracts were printed and circulated widely across Europe, reaching France, England and Italy as early as 1519. The following year (1520) Pope Leo X demanded that Luther renounce all of his writings. Luther refused and was excommunicated from the Catholic Church in January 1521 (at the time of his death in 1546, his excommunication was still in effect). Later that year (1521), at the Diet of Worms, the Holy Roman Emperor, Charles V, condemned Luther as an outlaw. Regardless, Luther clearly made effective use of Gutenberg’s printing press to spread his views. He even switched from Latin to German in his writing to appeal to a broader readership. Between 1500 and 1530, Luther’s works represented one fifth of all materials printed in Germany, but more significantly demonstrated the power of the printed word to reach and influence a vast audience and spark Reformation.

Printers’ legacies

The development of printing has had other, perhaps less obvious, impacts. Several words and phrases are thought to have entered the English language from printing. For example, the terms “uppercase” and “lowercase” letters seemingly derive from printers storing type in shallow compartmentalised drawers called “type cases”. In most print shops, the majuscule (capital) letters were kept in a separate case typically positioned above the case containing the miniscule (“small”) letters. Hence, we refer to capital letters as “uppercase” and the smaller forms of the letters in the English alphabet as “lowercase”.

The metal sorts used in printing are cast as mirror images so that the resulting print will be the correct way round. In older type cases, lowercase p’s and q’s are in sections right next to each other and therefore were prone to getting mixed up. So, compositors in the print shop were encouraged to take care and “mind their p’s and q’s”, eventually leading to the phrase meaning to be on one’s best behaviour. Interestingly, several letters look like mirror images of each other but mixing them up was less likely. B’s and d’s, for example, may be mirror image letters but they are not kept side-by-side in type cases.

Limited supplies and storage space within a print shop often made it impractical to leave type set in its “forme” just in case a reprint was required. Yet, given the time and labour involved in setting type, especially if one considers the prospect of re-setting an entire book for a subsequent edition, it was sometimes worth the expense of using a “stereotype”. The process involved creating a mould, known as a “flong”, in papier mâché of already set type. A mixture of molten lead, antimony and tin was poured into the mould to cast the type as a single metal plate or “stereotype” that could be used for reprints. The original type set could then be taken apart and distributed for use in other jobs. The idea of printing many identical copies from a single plate of type was soon connected to the broader meaning “stereotype” describing individuals belonging to a single group as being effectively the same as one another.

Cliché is the French word for stereotype. The difference in this case is that rather than casting a whole plate of text, the French would cast frequently used phrases as a block that could be set in a forme alongside any other individual letters to save time. The word cliché is derived from the French verb “clicher” meaning “to click” and imitates the sound made when using stereotype plates in a method known as dabbing or abklatschen (“to tap”) in German. Phrases cast in this way were so frequently used that cliché become synonymous with its modern meaning.

The casting of printer’s stereotypes or clichés is believed to have given rise to the word “typecasting”. Once again the idea of printing multiple identical copies has been transferred to actors chosen for roles relying on their specific profile, particularly when they are picked for very similar roles time and again. In these instances, they are being typecast.

One last example is contested, but it may have had an origin in print shops. If someone is feeling unwell or ill-tempered, they might be described as “out of sorts”. As previously mentioned, individual characters or “glyphs” of cast metal type are called “sorts”. When typesetting, a compositor might run out of type part way through a job thus making them “out of sorts”. In such circumstances the compositor may well have felt fed up about it and it is therefore tempting to think that this could be the source of the phrase. According to the website Phrase Finder, however, the first known citation of “out of sorts” appears in “The Proverbs, Epigrams, and Miscellanies of John Heywood” dated to AD 1562. No mention is made to typesetting and it seems the phrase pre-dates the first use of the word “sorts” to mean blocks of type. So, it is safer to conclude that “sorts” is just a synonym for “spirits or health”. That said, an earlier citation may yet be discovered, especially given that Gutenberg invented movable type printing over a century earlier around AD 1440.

Da Vinci’s parachute

Forty-five years after Gutenberg introduced Europe to the printing press, in 1485 Leonardo da Vinci sketched the world’s first parachute in his work, the Codex Atlanticus. His design was for a pyramid-shaped canopy, approximately 12 braccia wide and 12 braccia tall [5], of sealed linen cloth stretched over a wooden frame. It seems Da Vinci’s vision was for a man to safely descend from any height providing the parachute was properly constructed. Unlike modern round parachutes, da Vinci’s version was rigid and structured to rely on air resistance to slow descent. There is no evidence that he ever built or tested his design, but centuries later da Vinci’s parachute was successfully tested to prove it was practicable. British balloonist Adrian Nicholas built a parachute of wood and canvas to the artist’s specifications. On June 26th, 2000 he was hoisted by a hot-air balloon to an altitude of 3,000 m (10,000 ft) and then released. Nicholas slowly and gently floated downward beneath da Vinci’s parachute thereby disproving predictions that the structure would not keep a man aloft. With the parachute weighing some 84 kg (185 lbs) there were concerns that it would crash down on top of Nicholas upon landing. To avoid injury, Nicholas cut away from the da Vinci parachute at 600 m (2,000 ft) and used a conventional parachute for the remaining, safe, descent.

Da Vinci’s flying machines

It is evident from his work that da Vinci’s approach to science was observational. He tried to understand phenomena through detailed description and depiction but not necessarily through experiments or theoretical explanation. The parachute was just one of the flying machines stemming from da Vinci’s fascination with the phenomenon of flight. Surviving to us are his many studies, including Codex on the Flight of Birds (c. 1505), as well as plans for several flying machines, such as a glider (below left & middle), the flapping Ornithopter [6], and one with a helical rotor (below right). 

Da Vinci is known to have studied the methods by which birds kept themselves airborne. He developed an in-depth understanding of bird flight, leaving behind a huge number of sketches, notes and musings about their behaviour. Da Vinci’s drawing of the Ornithopter (pictured right) conceived human flight inspired by his copious observations. The design had the pilot lying prone while operating a complex system of pedals and pulleys to flap the wings and adjust the tail. His engineering solution attempted to scale up the natural strength of humans to generate sufficient lift for take-off and sustained flight. After several attempts at re-creating the flapping action of birds, da Vinci concluded that his design could not generate enough power or lift to overcome the weight of a pilot and achieve flight. While practically impossible, given the machine’s size and weight, the ornithopter nonetheless remains a brilliant conceptual exercise and an innovative leap of imagination far ahead of its time.

Once it became clear that the ornithopter was doomed to failure, and probably injury in any testing scenarios, da Vinci reverted to his studies of the most efficient form of bird flight, i.e. gliding through the air. He quickly realised that fixed-wing gliders were more likely to succeed in keeping a moving object off the ground. Even so, da Vinci’s alternative approach was still constrained by the materials of the period being far heavier than those available today. Even so, da Vinci pioneering observations on aerodynamics recognised the importance of airflow both over and under wings to create lift. He identified vortices formed by wing movement, a concept still relevant to aerospace engineering today, and noted the role of a bird’s “thumbs”, or alulae, in controlling descent and ascent. Da Vinci’s work demonstrated a deep understanding of the physics involved that paved the way for later advances in flight mechanics (Bianchi, 2026).

Da Vinci’s tank 

More correctly termed an armoured fighting vehicle, the concept of da Vinci's Tank first appeared a letter to his patron, Ludovico Sforza, the Duke of Milan. Written around 1482 as part of his Codex Atlanticus, da Vinci proposed:

“I will make protected wagons, reliable and impregnable, which, piercing the enemy’s ranks with the fire of their artillery, will destroy him, no matter how great the number of his soldiers. The infantry can follow without suffering great losses and without encountering any resistance.”

The resulting design, inspired by a turtle’s shell, incorporated a conical cover made of wood reinforced with metal plates. The angled cover was intended to deflect enemy fire in much the same way as modern sloped armour. Da Vinci envisioned the machine would be driven by two large cranks, operated internally by four strong men, powering two wheels each connected by an axle. The circular fighting vehicle would be equipped with an array of light cannons spaced around its circumference.

Study of da Vinci’s sketches revealed a flaw in the gear design, which would cause both wheels to rotate in opposing directions rendering the machine inoperable. This error has been described as a deliberate security feature should the design be stolen or because of da Vinci’s mirror writing style that appears in his other designs. The superb 3D model by Ľuboš Černák, shown right, was created in 2022 according to da Vinci’s original drawing. The model emphasizes the machine’s proportions but also illustrates the flawed gearing design alongside three possible solutions to the problem. During one episode of the US documentary series “Da Vinci's Machines” (2009), a team of engineers and craftsmen undertook the challenge of reconstructing Leonardo’s armoured vehicle. During the build the flawed gearing design was corrected enabling the team to successfully operate and move the machine. From the vehicle’s impressive size, it was clear that it would not have been capable of moving across rugged terrain. Moreover, while it would not have been possible to realise da Vinci’s idea in the 15th-century, the reconstruction validated his innovative thinking.

Bon appétit!

References:

Bianchi, L. (2026), “Leonardo da Vinci Glider: Could It Really Fly?”, Leonardo da Vinci Inventions and Experiences, available online (accessed 18th June 2026).

Borman, T, (2026), “Ask the Experts: The printing press”, in History Extra Magazine (April 2026), London: Immediate Media Company, p.44.

Gurney, T. (2023), “Leonardo da Vinci”, https://www.thehistoryofart.org, available online (accessed 14th May 2026).

Lentz-Smith, A, (2026), “Ask the Experts: Writing”, in History Extra Magazine (April 2026), London: Immediate Media Company, p.42.

Regulski, I., (2016), “The Origins and Early Development of Writing in Egypt”, available on-line (accessed 16th June 2026).

Venner, J, (2026), “Ask the Experts: Roman concrete”, in History Extra Magazine (April 2026), London: Immediate Media Company, p.42.

Endnotes:

1. In his 1897/98 publication “Der westafrikanische Kulturkreis”, Leo Frobenius conceptualised “cultural diffusion” as the spread of cultural ideas, styles, religions, technologies, languages between individuals, whether within a single culture or from one culture to another.

2. In physical typesetting, a sort or type is a block with a typographic character etched on it that are used, when lined up with others, to print text. In movable-type printing, the sort or type is cast from a matrix mould and assembled by hand with other sorts bearing additional characters into lines of type to make up a form, from which a page is printed.

3. A glyph is any kind of purposeful mark. In typography, a glyph is “the specific shape, design, or representation of a character.” It is a particular graphical representation, in a particular typeface (in computing, a font), of an element of written language.

4. The remission of the temporal punishment of sin.

5. The term braccia refers to an Italian unit of measurement derived from the length of a man’s arm that could vary between 318 mm and 991 mm (15 in and 39 in). Historically, braccia were used to measure cloth as well as other items. Interestingly, in 18th-century Milan one braccio was redefined as one metre and is only 90 mm shorter than the modern SI unit.

6. From the ancient Greek ὄρνις (órnis) meaning “bird” and πτερόν (pterón) or “wing”, an ornithopter is an aircraft that flies by flapping its wings. Designers like da Vinci sought to imitate the flapping-wing flight of birds, bats, and insects.