I am presently reading "A history of the ancient near east" by Marc van de Mieroop. On page 292 he writes: "No Median Empire ever existed. Why was it concocted then? Herodotus imagined there had been a sequence of world empires in Asia before the Persian one that the Greeks confronted, He knew about Assyria and Persia, but between them was a void. This he filled with the Medes, and thereby created a phantom empire whose image is still accepted today.
De Mieroop does not deny the existence of the Medes, but that they formed an empire. What is the general opinion among historians about this?