The Hittites of southwest Asia (in modern-day Turkey) were the first to employ iron in their weapons, around 1200 B.C.E. They used it in making swords, spears and arrow heads, replacing the more brittle bronze. By coincidence, this was also about the time the Hittites conquered parts of Egypt.
Iron was more plentiful than the ores used to make bronze, and it was more cheaply mined. As a result, all people (not just the more powerful nations) were able to use iron weapons.
Within a few hundred years, the art of forging iron to make weapons developed. At this point, iron swords, battle axes, spears and arrowheads became much more advanced and dependable.
With iron weapons being cheaply produced, nations were able to furnish more weapons to their military. Thus armies became larger and conscription began.
The Iron Age seems to have made war more feasible, and there was constant war. During the Middle Ages, not only was the iron used for weapons, it also came to be used for knight's armor.
