Composed nearly 3000 years ago, Homer's Iliad is a foundational work in the Western literary tradition. The form of classical Greek Homer used to write the epic poem defined the culture of drama, philosophy, and scientific inquiry that followed in his wake. The theology, literature, natural science, and political theory of ancient Greece, illustrated so vividly in the Iliad, was absorbed by the Roman culture that came to dominate in the regions where Greek culture had reigned for centuries. The Romans extended the reach of Greek-influenced culture into northern and western Europe. The Roman responses to Homer by Latin writers like Virgil and Ovid made the exploits of the (renamed) Greek gods and heroes popular among the new Greco-Roman cultural elite. Books like the Iliad were cornerstones of the education of any wealthy young man in the far-flung Roman Empire, and they were at the core of the Renaissance-era rediscovery of the body of ancient classics that have defined the Western canon since then.
For modern scholars, the Iliad also provides a rich source of geographic, demographic, and political information about the ancient world to complement the historical and archaeological record, and the mythical depictions. It was the ardent belief by nineteenth-century archaeologists in the existence of an actual city of Troy which led to its excavation, partly corroborating Homer's source material. In addition to its importance as a cultural and historic document, its themes and formal structure had a profound influence on the evolution of English literature, and some metaphors and idioms derived from the poem are still used today. Someone doesn't need to have read the Iliad to have heard of an “Achilles heel,” indicating the poem's continuing presence in the popular imagination.