The author knew as well as everyone else that Nineveh and the Assyrian Empire had actually fallen. Had the Assyrians actually repented, it would have amounted to a mass shift in religious commitment and political strategy, which would have been big news (“Assyrians bow the knee to Israel’s God. Hostilities cease. Film at 11:00”). But nothing of the sort is known from any ancient record, Assyrian or otherwise. It strains credulity.
