It's something of a mystery why the use of iron implements did not come before that of bronze. Iron is relatively abundant and is much more easily refined from iron ore. In fact, meteorites and masses of relatively pure iron called "bog iron" can be worked without the need of refining or smelting at all. In addition, the hard alloy of iron called steel is difficult not to produce. Steel is a combination of carbon and iron, and the iron naturally picks up carbon from whatever fuel it is being heated by. In fact, steel may be quite ancient, since a steel dagger was found in an Egyptian tomb dating back to 3000 B.C. For some reason or another, however, it did not come into common use for almost two centuries. It is interesting to speculate as to the possible reasons for this curious fact.
Nevertheless, iron did become a common metal for tools and weapons sometime in about 1200 B.C. Its introduction coincided with a wave of migrations that helped to topple the Bronze-Age Empires and bring about a new era known as the Iron Age. The birth of this new period of human history saw the elevation of the individual and the emergence of many democratizing innovations.
One result of the introduction of iron weapons was that the battlefield supremacy of the chariot warriors was ended. It was now possible to put large numbers of people, armed with iron-strengthened shields, iron-tipped spears and javelins, and steel swords onto the field of battle. If such men could be trained to move while staying close together, their shields could be used to form a protective wall, and their spears pointed forward to form a dense mass of sharp points. Horses could not be made to impale themselves on these points, and no champion, however, skilled could prevail against such a mass. The chariot warriors disappeared, except in remote places such as distant Britain. As we noted, political power generally goes to those who have military power, and it was now the common infantry who exercised military power. Local nobles in Egypt and China in longer needed the bronze that their monarchs controlled, and their power increased while that of the central government diminished. As the power of the central government vanished, so too did the bureaucracy and priesthood that kept the masses in their place. The state religions fell into confusion, and the elaborate system by which the priesthoods and monarchs had defined the nature of the gods, the laws governing the universe, and the place of the individual within that universe collapsed. The Empires disintegrated into groups of warring states, and the people were left to seek new definitions to replace those that had disappeared.
The spread of iron-age civilization was an important factor in what occurred. Wealth and power were no longer concentrated in those states with bronze weapons, and commerce was no longer aimed so directly at the acquisition of bronze. Small states sprang up and were able to defend themselves because a greater proportion of their citizens were able and willing to arm themselves and fight. Most populous states tended to overwhelm the smaller states, of course, but even this tended to bring people into closer contact than had hitherto been the case. Trade-routes, meanwhile, multiplied, and the quality and variety of goods exchanged increased markedly. A group of maritime commercial states arose in Phoenicia, on the coast of Syria. Their commerce was too extensive to rely upon a small group of scribes who were able to keep records for them, and they developed a new form of script. The earliest form of writing had been pictographic, stylized drawings of things. This had developed into ideographic script, such as is still employed in China, in which such pictures were used to denote ideas. A picture of a leaf could be combined with that of a bee, for instance, to denote "ideology" (bee+leaf). This could be quite effective, but required that the scribe learn literally thousands of such signs, many of them quite arbitrary. As time went on, a syllabic script developed in some places. This sort of script uses one sign for each different syllable in the language. "Different," for instance, would use a different sign for each of its syllabic components: di-fi-fe-re-ne-te. This was a great improvement, but there were still hundreds of syllabic signs to learn. The Phoenicians simplified things much further by introducing alphabetic, in which the language was broken down into its basic sounds and a symbol assigned to each. Writing was thus much simplified, and the ability to read and write was within the reach of most people.
So commerce, technology, literature, and even warfare acted to bring people closer together, which may explain why, beginning in about the 700's B.C., a new approach to religion arose almost simultaneously among various peoples of the Eurasian continent.
The dominant form of religious worship up to this time had been propitiatory. The god was considered to be a powerful and possible vengeful force, who had to be bribed in the form of sacrificed offered up with more or less elaborate ceremony. Some gods liked the smoke of burning cows, others like the scent of roasted children, the hearts that had been torn out of prisoners of war, or the screams of captives being tortured to death, or simply lots of human blood splashed on their altars. They could sometimes be fooled, such as the Chinese gods could be made to think that a burning straw doll was really a horse, but this was always a dangerous procedure. These gods didn't care what you did as long as they got lots of whatever its was that they wanted. Most of them were sticklers for detail. A little mistake in the ritual of sacrifice might earn you a flood or a windstorm that would destroy your crops. So most such rituals were left in the hands of a professional priesthood trained not to make such mistakes. Of course, the professional priesthood assured everyone that this was the way that the gods were.
The professional priesthoods collapsed along with the empires that the gods had been supposed to protect, and many people, one would think, began to wonder how the universe really worked, and what the individual could do to bring some order to a world that was falling apart. Several individuals in widely dispersed places, reached approximately the same conclusion at roughly the same time. Confucius and Lao-tze in China, Gautama Siddhartha Buddha in India, the prophet Joel in Israel, the poet Hesiod in Greece, and others, all reached the conclusion that the individual was responsible for his or her own actions, and that god, or the gods, not only expected the individual to behave ethically and morally, but would reward those men and women who did so. An unknown scribe writing in Egypt at this time, said Justice does not go down into the grave with him who does it.
There is not sufficient time in a survey course to examine the ethical religions in detail. It should suffice to say that these religions held that mankind had risen above the animals with the ability to distinguish between right and wrong, good and evil. This ability is the fundamental characteristic of humans and what distinguishes them from the rest of creation, and only when they exercise this function are they fully human. Those who believe that a deity created mankind believe that the same deity gave humans this power so that they would use it. Those who do use it please the deity, while those who abuse or disregard it displease their maker. Those who are unconcerned with the idea of a creator simply say that human societies cannot endure unless their members act like human beings toward each other.
The Iron Age saw great strides forward toward the freedom and dignity of the individual, but many people of the time saw only the disruption and destruction of the era. They developed the idea that human history was a series of stages, each worse than the one preceding. They looked back upon a sequence beginning with a Golden Age that gave way to an Age of Silver, then an Age of Bronze, and finally an Age of Iron, and wondered when the next period of decline would come. This pessimistic view was quite common among historians, even in the generally ebullient Western tradition, until the scientific discoveries of the sixteenth century gave birth to the Age of Enlightenment and a belief in the Idea of Progress.
Although you cannot be expected to investigate all of these sites in detail, you will find it useful at least to visit Chinese Philosophy, and Buddhism.