One reason why Homer's work is considered significant is because it is believed to be "the first work of true literature in the Western tradition." The Iliad establishes the capacity and the possibility of literature in the Western tradition. Its impact is also significant in that it establishes many of the thematic and content traditions that are part of modern literature. The conflict between desire and duty was first articulated in the Iliad. The notion of warfighting as a means of conflict resolution, as well as the idea that there is a difference between the romantic visions of such an idea and the realistic execution of it are realities that help to make the work significant. The work's treatment of issues such as honor, justice, vengeance, and ethical structure of human consciousness are all critical to its significant place in Western literature. Another reason why the work is so significant is because the metaphors and ideas that arise from it are so felt in the modern setting. Concepts such as "Achilles' Heel" or "Trojan Horse" or "The face that launched a thousand ships" are all constructions used in the modern setting that owe their existence to Homer's work. In this light, one can see how significant the work actually is and how relevant it continues to be long after its composition.