Martin Litchfield West has argued that the "Iliad" echoes the poetry of Hesiod, and that it must have been composed around 660–650 BC at the earliest, with the "Odyssey" up to a generation later. He also interprets passages in the "Iliad" as showing knowledge of historical events that occurred in the ancient Near East during the middle of the seventh century BC, including the destruction of Babylon by Sennacherib in 689 BC and the Sack of Thebes by Ashurbanipal in 663/4 BC. At the other extreme, a few American scholars such as Gregory Nagy see "Homer" as a continually evolving tradition, which grew much more stable as the tradition progressed, but which did not fully cease to continue changing and evolving until as late as the middle of the second century BC.