Zechariah 1:19

In response to the prophet’s request for an interpretation, the assisting angel explained that they represented the powers that had scattered Judah, Israel, and Jerusalem. Assyria took Israel into captivity, and Babylonia destroyed Jerusalem and took the Judahites captive. So perhaps the fact that there were four horns symbolizes that they represented nations from the four corners of the world, the totality of opposition. [Note: Smith, p. 193.] Another view is that they stand for Babylonia, Medo-Persia, Greece, and Rome (cf. Daniel 2; Daniel 7). [Note: Charles H. Dyer, in The Old Testament Explorer, p. 823; and Feinberg, "Zechariah," p. 900.]