Listen and Subscribe
Podcast Transcript
Most people probably don’t have anything made of bronze at home.
Yet bronze used to be a big deal… a really big deal. In fact, an entire age of history is named after bronze.
The discovery of this metal alloy wasn’t a minor upgrade over previously used metals. It was a technical revolution that laid the groundwork for the modern world.
Learn more about bronze and how a simple metal changed the trajectory of the world on this episode of Everything Everywhere Daily.
I’ve done episodes on the Three Ages system: the Stone, Bronze, and Iron Ages. I’ve also done episodes on the Late Bronze Age collapse, and I’ve mentioned the Bronze Age multiple times.
In this episode, I want to focus on the Bronze Age itself and, in particular, why bronze came to define an entire era of human history.
We should start with what bronze is.
Bronze is simply an alloy of copper and tin. In particular, it is usually considered to be a combination of 9 parts copper to 1 part tin. There isn’t an exact recipe for bronze. It can be as little as 5% tin or as much as 15%. More tin makes the bronze harder, but also more brittle.
This sounds like a very simple innovation, and it is, but this simple recipe had revolutionary implications.
To understand why bronze was revolutionary, we need to understand what was used before.
While the Three Ages system calls the previous world the Stone Age, in reality it could have been called the Copper Age.
Humans used naturally occurring native copper long before they understood how to smelt copper from ore. People could hammer native copper into small objects, including beads, pins, hooks, and simple tools.
Eventually, people developed techniques for extracting copper from minerals using heat. Copper smelting was established in parts of southeastern Europe and southwestern Asia during the fifth millennium BC, although the precise chronology varies by region.
Although copper was one of the first metals used to make tools, it had several significant weaknesses. Pure copper is relatively soft, meaning that cutting edges dull quickly and tools can bend or deform under heavy use. A copper axe, for example, would require frequent sharpening and could become damaged when chopping hard wood.
Copper can be hardened by hammering, a process known as work hardening, but this also makes it more brittle and susceptible to cracking if worked excessively. Copper also presents challenges when casting, as it has a relatively high melting point and does not flow easily into molds.
As a result, stone tools, particularly those made from flint or obsidian, could sometimes produce sharper and more effective cutting edges than copper.
We don’t know who, where, or when bronze was first discovered, but it was almost certainly discovered by accident.
An especially important archaeological discovery came from Plo?nik, in modern Serbia. Researchers identified a piece of tin-bronze foil dating to approximately 4650 BC.
Chemical analysis suggests that it was produced using naturally occurring copper-tin minerals rather than by intentionally mixing separately prepared copper and tin.
Researchers have identified other early bronze artifacts from the Balkans. These finds show that bronze was produced much earlier than previously assumed.
However, this early Balkan bronze technology appears to have been relatively short-lived. It did not represent the beginning of continuous, widespread bronze production throughout Eurasia.
The decisive advance came when metalworkers learned to deliberately add tin or tin-bearing materials to copper.
This let them create bronze more consistently, rather than relying on impurities in naturally occurring ores.
By the third millennium BC, bronze was becoming increasingly important in parts of the ancient Near East, with adoption continuing at different rates across Europe and Asia.
So why did people prefer bronze to copper or even stone?
Bronze is harder, stronger, and more wear-resistant. Bronze tools and weapons can hold sharper cutting edges for longer periods and are less likely to bend or deform under stress.
Bronze also generally melts at a lower temperature and flows more easily into molds, making it easier to cast complex shapes. These advantages made bronze especially valuable for manufacturing durable tools, weapons, and other metal objects.
Bronze axes, chisels, and drills offered important advantages to carpenters and other craftspeople.
These tools could be used to manufacture or repair wooden agricultural equipment, construct storage buildings, and prepare timber for carts and other structures.
Improved tools meant improved agricultural productivity, although most agricultural tools weren’t necessarily made of bronze.
One of bronze’s biggest impacts was in warfare. Before the widespread use of bronze, weapons were primarily made from wood, stone, bone, and, later, copper.
One of bronze’s most important applications was making swords. Copper was generally ill-suited for making long, durable blades. Spears were much more common before bronze rose to prominence.
By the second millennium BC, people produced bronze swords in several parts of Eurasia. Their designs varied widely, from relatively short thrusting weapons to longer blades suited to both thrusting and cutting.
Swords became both military weapons and indicators of social status. A sophisticated bronze sword required specialized craftsmanship and valuable metal, so owning one could signal wealth and authority.
It was more than just swords, however. Bronze spearheads, axes, and daggers were often easier to produce and required less metal than swords.
Bronze spearheads could be sharpened and securely mounted on wooden shafts. Improved casting techniques enabled socketed weapons, allowing a stronger connection between the metal head and wooden handle.
Bronze was also used for helmets, shields, and armor. Bronze armor could offer significant protection but was expensive and required substantial amounts of metal.
So, bronze wasn’t just another metal. It was a significant upgrade over copper. Adopting bronze meant greater economic and agricultural productivity, and it also made communities militarily more powerful.
However, there was a catch.
Copper was relatively easy to find. Tin, on the other hand, was scarce. It was found in minable amounts in only a few places that were rather far away from major population centers.
Some of the most important ancient tin-producing regions or potential sources included:
- Cornwall in southwestern Britain.
- Parts of modern Uzbekistan and Tajikistan.
- Afghanistan
- Turkey and parts of southeastern Europe.
- And The Iberian Peninsula
Yet most of the world’s most powerful Bronze Age states were located far from major tin deposits.
This created a strong incentive to establish and maintain long-distance commercial networks. Tin could be transported through multiple intermediaries, sometimes crossing mountains, deserts, rivers, and seas.
A merchant trading tin in Mesopotamia might never have known the ultimate geographic origin of the metal. The result was a chain of trade connecting distant mining communities and urban centers.
One of the clearest documented examples of Bronze Age international trade comes from the Old Assyrian merchant networks of the early second millennium BC.
Merchants based in Ashur, in northern Mesopotamia, traveled to trading settlements in Anatolia. One of their most important commercial centers was Kanesh, near modern Kayseri in Turkey.
They transported tin and textiles into Anatolia and exchanged them for valuable metals, especially silver and gold.
Thousands of clay tablets discovered at Kanesh preserve records of merchant activities, including loans, credit arrangements, business partnerships, contracts, and correspondence.
The documents show that Bronze Age merchants operated commercial networks remarkably sophisticated for their time.
While trade existed beforehand, the need for tin to make bronze drove the development of the trade system that emerged during the Bronze Age.
Of course, tin was only one half of any trade. They needed something to trade for the tin. Bronze helped encourage a division of labor between regions.
One area might specialize in mining copper, another in producing tin, a third in refining metal or manufacturing finished goods, and a fourth might serve as a trade hub.
These activities connected communities that otherwise had relatively little reason to maintain regular economic contact.
The resulting commercial networks could also carry textiles, timber, food, ceramics, precious stones, and luxury goods.
One of the most extraordinary archaeological discoveries relating to the Bronze Age is the Uluburun shipwreck, discovered off the coast of southwestern Turkey in 1982.
The ship sank around 1320 BC. Its cargo included approximately 10 tons of copper and 1 ton of tin. The metals were present in approximately the proportions necessary to make 11 tons of bronze with a composition close to 90% copper and 10% tin.
The ship also carried other valuable goods, including glass ingots, ivory, ebony, luxury materials, and manufactured objects.
Its cargo was a microcosm of Late Bronze Age Mediterranean trade.
For decades, archaeologists debated the origins of the tin circulating in Bronze Age Mediterranean markets.
A 2022 study of the Uluburun tin cargo proposed that a substantial portion came from the Taurus Mountains of Anatolia and another portion from Central Asia.
However, more recent research has complicated this picture.
A 2025 study using trace-element and isotopic analyses presented evidence consistent with significant tin shipments from southwestern Britain.
The significant point is that archaeologists are finding evidence of metal moving across extraordinary distances, potentially thousands of kilometers, through interconnected trading systems.
Because bronze was so important and powerful, there were second-order effects. Whoever could control the production and trade in tin had enormous power. While large states and empires existed before the spread of bronze, bronze made it easier for rulers to control their societies.
If you remember back to my episode on the end of the Bronze Age, around the year 1200 BC, there was a sudden collapse or near collapse of most Bronze Age civilizations in the Eastern Mediterranean. While the jury is out on what caused the collapse, the most likely reason is invasion by a group known only as the Sea Peoples.
This wasn’t only a political collapse. It also caused the tin and bronze trade to collapse.
The start of the Iron Age didn’t come about because iron was better than bronze, although iron does have many benefits. The main reason why people shifted to iron is that it was easier to source.
Iron didn’t require complicated trade networks to source materials from far away.
Producing iron was technically more challenging.
Bronze could be melted and cast using technology already familiar to experienced copper workers.
Early iron production generally required furnaces operating at much higher temperatures, reducing the iron ore to a solid, spongy mass called a bloom. Workers then repeatedly heated and hammered the bloom to remove impurities and consolidate the metal.
Early wrought iron was not necessarily stronger or harder than a well-made bronze weapon. It took centuries of improvement to iron smelting before iron weapons and tools could surpass bronze.
Even then, bronze was never considered obsolete. Trade routes eventually were reestablished and bronze production resumed alongside iron production.
Bronze remained exceptionally useful for applications where castability, corrosion resistance, and wear resistance were important.
It continued to be used for sculpture, coins, and numerous specialized components.
Today, bronze alloys remain useful for some marine equipment, bearings, bushings, springs, and industrial machinery.
For several hundred years, a popular use of bronze has been bells. When struck, bronze produces a clear, powerful, resonant sound that can persist for a considerable time. This makes it particularly well suited for bells that need to be heard over long distances, such as those used in temples, churches, and clock towers.
Traditional bell bronze, also called bell metal, typically contains approximately 78% copper and 22% tin, considerably more tin than the bronze used for many ancient tools and weapons. The high tin content makes the alloy harder and relatively brittle, but also produces desirable vibrational characteristics.
The Liberty Bell in Philadelphia is made out of bronze as is the Big Ben bell in London.
The importance of bronze went far beyond the tools, weapons, and objects made from it. By combining two metals, ancient people created a material that transformed warfare, encouraged technological innovation, and helped establish trade networks connecting distant civilizations.
Bronze was more than just a metal alloy. It was a technological revolution that changed the world so much that it deserves an era of history to be named after it.