Early Armor starts to appear four to five thousand years ago, physical protection was most likely in use far longer than that but that's when we start seeing phyical proof of it's use. Most early were made from organic materials, which included wood, animal hides, or cloth. All of these materials degrade quite quickly unless they somehow manage to win the preservation lottery. Humans have been around for a decent amount of time, some estimates reaching 6 million years, so the possibility that people protected themselves with furs or other materials in an almost 6 million year time span isn't far fetched.
Surprisingly some of the earliest armor we have solid evidence of is from a relatively peaceful nation. Situated in the northeastern part of Africa, Ehypt had an abundance of sand, sun, and culture. Possibly due to the warm, dry enviroment or maybe due to Egypt's inclination to bury thousands of items with their deceased, we have some very decent specimen's from Egpyt. Ancient Egyptian armor was some of the earliest armor and set the standard for later armor.
A good majority of early civilization occurred in the fertile crescent, the area of land between the Tigris and Euphrates river. Ironic the area that was known as the cradle of civilization is now a big pile of sand. Well its no big surprise that a good amount of the information that we have about ancient armor is from this general area of the world. The Sumerians were one of the oldest civilizations in the area. They developed a number of important technologies including the wheel, cuneiform, and bronze-working. Although they eventually were conquered by the Akkadians and later the Babylonians, the Sumerian culture tended to be a hard beast to put down and prevailed even into the Babylonian empire. Before the Sumerian people was subdued they developed some interesting Sumerian armor.
Next we come to the bad boys of the middle east, the Assyrians. They burst onto the scene around 1400 BC (3400 years ago) and like the grade school bully took everyone's lunch money, lunch money being their cities. The Assyrians were some of the first to outfit the majority of their soldiers with full body armor. This must have been a good move because they controlled most of the middle east plus northern Egypt for a good 800 years. Assyrian armor included some very interesting advancements of ancient times.
Continuing onwards through history, we encounter the people of Mycenae. This time period is well known due to the historical fiction of the Illiad and the Odyssey. If you read either book you know how dangerous it was to live in these times. Now these people needed body armor. The armor of Mycenae is some of the earliest evidence of plate armor, armor made from solid pieces of metal.
We already discussed the basis of early Greek culture, so now we'll move onto it's later culture. We're talking about Sparta, Athens, Corinth, and Thebes. Thanks to a wellspring of Hollywood movies about the Greeks, most people nowadays have a basic idea of what the basic Greek soldier adorned in Greek armor would look like. Crested helmet, metal greaves and a metal breastplate. The Greeks were less of an empire and more of a culture with differences similar to the United States. When the Greek "states" were endangered they would band together to fight off the threat. Once the threat was neutralized they would again revert to governing themselves.
We've discussed a lot of the western nation's early armor, but the east was also developing some of it's own ancient armor. The Chinese were on the forefront of many ancient technological advancements. They were the first to invent gunpowder, porcelain, silk, seismic detectors and many others. Its not surprising that they developed a lot of advancements in the art of defense. They were one of the first civilizations to master smelting iron armor. They also created Chinese armor made from paper that was unusually strong.