1 Samuel 31:7

And when the men of Israel that were on the other side of the valley, in the hill-country toward the north and northeast, and they that were on the other side Jordan, apparently such as had not been mustered in the army, saw that the men of Israel fled, and that Saul and his sons were dead, they forsook the cities, for fear that they could not hold them anyway, and fled; and the Philistines, eventually, at the end of the campaign, came and dwelt in them.