According to scientists, the Illiad was written within 50 years of 762 B.C. Here's how they dated the great work:
The scientists tracked the words in the "Iliad" the way they would track genes in a genome. The researchers employed a linguistic tool called the Swadesh word list, put together in the 1940s and 1950s by American linguist Morris Swadesh. The list contains approximately 200 concepts that have words apparently in every language and every culture, Pagel said. These are usually words for body parts, colors, necessary relationships like "father" and "mother." They looked for Swadesh words in the "Iliad" and found 173 of them. Then, they measured how they changed.
They took the language of the Hittites, a people that existed during the time the war may have been fought, and modern Greek, and traced the changes in the words from Hittite to Homeric to modern. It is precisely how they measure the genetic history of humans, going back and seeing how and when genes alter over time.
For example, they looked at cognates, words derived from ancestral words. There is "water" in English, "wasser" in German, "vatten" in Swedish, all cognates emanating from "wator" in proto-German. However, the Old English "hund" later became "hound" but eventually was replaced by "dog," not a cognate.