The Iliad reflects more than one historical period. First, the Bronze Age (around 1200 B.C.) is the setting for the Trojan War that is recounted in the epic. Because the Iliad was preserved orally for centuries until it was written down sometime in the early eighth century, it changed over time as bards altered people, places, and situations to please their changing audiences. The result is that some elements found in the poem reflect different time periods. Archeology recently supports that many descriptions found in the Iliad were effectively passed down from the Bronze Age, while some reflect later Greek traditions from a time when the population was recovering from the devastation that ended the Mycenaean era. In any case, the epic reflects several centuries of rich early and archaic history.
You can retrieve historical information from the Iliad by focusing on certain themes in the epic. For example, note the clear class distinction between the warlords and the common soldier, the roles of noble women, and the myriad of gods and goddesses. These all accurately describe what we know to be true of aristocratic life in ancient Greece. Homer is also credited with organizing the complex relationships of the Greek pantheon of gods.