The first, termed Proto-Isaiah (chapters 1–39), contains the words of the 8th-century BCE prophet with 7th-century BCE expansions; the second, Deutero-Isaiah (chapters 40–55), is the work of a 6th-century BCE author writing near the end of the Babylonian captivity ; and the third, the poetic Trito-Isaiah (chapters 56–66), was composed in Jerusalem shortly after the return from exile, probably by multiple authors.