"The ancient and formerly unquestioned tradition of the Christian church, inherited earlier from the Jewish tradition, was that the entire book of Isaiah was written by a single author, the prophet Isaiah. [5] Josephus (ca. A.D. 90) stated that King Cyrus read about himself in the prophecies of Isaiah."

Basically, much of Christendom and for a long time asserted that this book was a single book made only by Isaiah and Isaiah lived long before Cyrus, therefore making this a prophecy. Whereas the secular world asserts there was a second isaiah otherwise referred to as deutero-isaiah (not actually Isaiah) and that someone at some point edited these texts and put them together for some reason. It then begins to draw into question the validity of the prophecy and potentially other books if this is considered to have happened here.