2 Kings 19:36 - Albert Barnes' Notes on the Bible

Dwelt at Nineveh - The meaning is not that Sennacherib made no more expeditions at all, which would he untrue, for his annals show us that he warred in Armenia, Babylonia, Susiana, and Cilicia, during his later years; but that he confined himself to his own part of Asia, and did not invade Palestine or threaten Jerusalem anymore. Nineveh, marked by some ruins opposite Mosul, appears here unmistakably as the Assyrian capital, which it became toward the close of the 9th century B.C. It has previously been mentioned only in Genesis (marginal reference). Sennacherib was the first king who made it his permanent residence. Its great size and large population are marked in the description of Jonah Jonah 3:2-3; Jonah 4:11, whose visit probably fell about 760 B.C.