The real advent of the Iron Age came not with the discovery of metal (in about 2500 B.C.), but with the invention of the process of casing or steeling it, probably about 1500 B.C. This happened when it was learned that by repeatedly reheating wrought iron in a charcoal fire and then hammering it, it not only became harder than bronze but kept its hardness after long use. (Wrought iron was discovered accidentally when smiths found that by hammering the small beadlike pieces of iron left as a residue after smelting copper they could form the iron particles into a mass. This kind of wrought iron, however, was good only for decorative purposes, and for more than a thousand years after 2500 B.C., iron remained a precious ornamental metal. Bronze, which was harder and capable of being sharpened to a fine cutting edge, continued to be the metal for tools and weapons.)

The next technological improvement, which again meant a further hardening of the metal, was the process of quenching it, which involved repeatedly plunging the hot iron into cold water. It was only after this series of discoveries and inventions that the significant impact of iron on culture and civilization was appreciably felt.

Because bronze was scarce, it was also costly. Consequently, it was not until iron came into use that humans extended their control over nature. For this reason, iron has been called the “democratic metal.” Widespread use of iron tools meant a general increase in living standards. For example, the use of iron axes brought about the clearing of forests, and therefore new land came under cultivation. Other significant developments included the application of iron tools to sheep shearing and cloth cutting, and the invention of the lathe, the most fundamental machine tool.

The Iron Age lasted until the beginning of the Classical Age (c. 2000 B.C.).