Disclaimer: This is not a comprehensive discussion about the entirety of the Iron Age. Yes, there are probably details missing. Please try to view this as more informational / enlightening than as an unfallable resource and we’ll all be happier!)
The beginning of the Iron Age (and, thus, the end of the Bronze Age) can be tied to the discovery and, ultimately, the implementation/usage of iron as a material. Depending on the sources used, multiple groups of people have been associated with the discovery of iron:
“… somewhere around 2000 BCE in southwest or southcentral Asia, perhaps in the Caucasus region.” (1)
“Iron artifacts dating back to the 5th millennium BC have been found in Iran by the archeologists.” (2)
“The earliest known iron artifacts are nine small beads, dated to 3200 BC, from burials in northern Egypt.” (3)
The discovery aside, widespread use of iron found a much better consensus among resources, generally considered to be around 1100 to 1200 BC in southwestern Asia. Early uses amongst certain populations ranged back as far as 1800 to 2000 BC. (3)
Iron, being one of the most common elements on Earth (it alone makes up 5% of the Earth’s crust), soon found itself a great replacement for the bronze of an earlier age. It is harder, more durable, and holds a sharper edge longer due to the increased content of carbon.
Iron has several forms:
- Iron ore – natural existence
- Wrought iron (carbon content .02-.08%) – produced by smelting iron ore in a charcoal fire, causing it to release oxygen and assimilate charcoal for the carbon content.This was the most commonly produced metal through most of the Iron Age. The material was malleable and strong, and made for good weaponry.
- Cast iron (carbon content 3-4.5%) – Created by heating at very high temperatures, usually in a blast furnace. Blast furnaces were not found in any significant amount until the Middle ages, limiting the volume of cast iron production. This material was much more brittle and could not be shaped with a hammer. It could be easily poured into molds and several items such as stoves, pots, and cannons / cannonballs were made from it.
- Steel (carbon content 0.2-1.5%) – Produced in the 1700s-1800s (depending on source) initially by the cementation process (heating wrought iron in powdered charcoal for several days to increase the carbon content).This material was far more flexible than wrought iron, but retained the hardness and strength.
Iron (and steel) continued to be the predominant metal in blacksmithing and construction until well into the 1800s, and some would even argue its continued importance to this day.
The Iron Age is generally considered to have ended sometime in the 6th century AD (this date is contested as well). It is generally not considered to have ended due to a scientific development, but more due to political / military events at the time. This period was followed by the Middle Ages.