Metallurgy had developed not only in Korea but all over the world since ancient times. Times are even determined and divided based on the development of tools such as the Stone Age, the Bronze Age, and the Iron Age. Before we go into the metal technology of Silla, let’s take a look at the history of metallurgy of the world. The oldest metal that humankind used was cooper. Around in 8000 BC, people of the New Stone Age had already started using natural cooper in substitute for stone. In Turkey, copper tubes from 6000 BC were discovered, and in places such as Anatolia and Iran, evidence was found that show the use of hammered copper in 5000 BC. By 3500 BC, copper was widely used in the Near East. The Cooper Age opened the door to the age of metal. At first, people used pure cooper, but gradually they mixed in other metals and came to use cooper alloy. The Bronze Age started in 3,100 BC in Upper Mesopotamia and Syria in West Asia. Bronze is an alloy of copper and tin, and brass is an alloy of copper and zinc. When people started to smelt metal, they not only smelted cooper but also lead, silver, and steel without realizing that such metals were mixed in. We presume that iron was already discovered in the early Bronze Age while people were mining. Then, when did people first encounter iron? The very first type of iron that humankind used was meteoric iron. Meteoric iron was used for rituals in ancient times. Ancient Sumerians called iron "an-bar," a word that symbolized sky and fire. At the time, iron was considered the celestial metal. The Greenlandic Inuit obtained iron swords with meteoric iron. And the Mayans, Incas, and Aztecs who had not gone through the Steel Age made ritual swords with meteoric iron. Evidence was also found that show the use of meteoric iron in the Yin Dynasty of China. Now then, when was terrestrial iron first used? We can find proofs of terrestrial iron use in 3,000 BC in Iraq. Around 1800 BC, iron was used economically in Babylonia. At that time, the value of iron was eight times the value of silver. By 2000 BC, humankind acquired advanced skills in metallurgy. And this is when metal trading started. The ancient empire of Hittite played a vital role in spreading iron. The Hittites belonged to the Indo-European language family and created an enormous ancient empire that stretched over Anatolia, Mesopotamia, and Syria. From 2000 BC to 1200 BC, the Hittite Empire solely possessed the iron-working skills. The empire collapsed in the 12th century BC by the Sea Peoples that pushed in along the southern coastline of Anatolia. Subsequently, the iron-working knowledge and technique of the empire rapidly spread to Egypt, Iran and beyond, and iron became common. This brought the Bronze Age to an end, and the widespread use of ironware marked the beginning of the Iron Age. After the fall of the Hittite Empire, ironware spread to all over the world. First, Phoenicians that lived on the coast of Palestine started to use ironware in the 10th century BC and later spread it towards south of Mediterranean to Carthage in North Africa. Once iron arrived in Africa, it traveled to Sudan in the 2nd century BC, to Central Africa in 500 AD, and to the Cape of Good Hope in South Africa by the 10th century. Ironware that spread towards Europe arrived in Greece in the 9th century BC, in Central Europe in the 8th century BC, and even in the British Isles by 500 BC. Eastwards, it spread to the northern regions of the Black Sea in the 8th century BC and through Central Asia to Korea and China. In China, when did people start to utilize iron? By the 5th century BC, they were already capable of casting iron. Historical records show that cast iron cauldrons were made in 512 BC. The first recorded blast furnace in China dates back to 91 BC. Unlike the West, the Chinese were capable of melting and casting iron from early on. In the West, iron casting skills were not acquired until the 14th century. The first furnace in the West was built in 1345. How were the Chinese able to produce cast iron from so early? Firstly, it had to do with the use of charcoal. Charcoal has a very strong heating power. Secondly, cast iron in China had a high content of elements such as phosphorus. This allowed the iron to melt at below 1,000 degrees Celsius. Lastly, they had excellent ventilation systems like piston-bellows powered by water wheels. As shown in the picture, the cast iron technology in China had developed from ancient times. Based on such advanced technology, the Chinese melted and cast iron to make farming tools, iron weapons, and cauldrons. Such cast iron technology also developed in Korea.
