“Now then, I will reveal the truth to you. Three more Persian kings will reign, to be succeeded by a fourth, far richer than the others. He will use his wealth to stir up everyone to fight against the kingdom of Greece.” Daniel 11:2
With the passing of Babylon, the natural question arose concerning the future of the Medo-Persian Empire. So the angel announced, “Now I will show you the truth,” that is, the truth of what would come to pass in the future. Daniel was informed that there would be three kings in Persia, followed by a fourth and greater king who would use his riches and strength to “stir up all against the kingdom of Greece.” The identity of these four kings has been disputed. The most natural explanation, however, is that the “three more kings” refer to the next three Persian rulers who followed Cyrus to the throne (cf. 10: 1). The three kings would then be Cambyses (529– 522 B.C., not mentioned in the Old Testament); Pseudo-Smerdis (522– 521 B.C.); and Darius I Hystaspes (521– 486 B.C., Ezra)”
These three kings would be followed by “a fourth … far richer than all of them,” which must refer to Xerxes I (486– 465 B.C., Ezra 4: 6). This identification has the advantage of taking the Persian kings in order, climaxing with Xerxes I who led the great expedition against Greece. Xerxes I used his great riches and a period of some four years to gather a great army amounting to hundreds of thousands, one of the largest armies in the ancient world. The expedition that he launched in 480 B.C. against Greece was disastrous, however, and Xerxes never recovered. The Ahasuerus of Esther 1 may be identified with Xerxes I, and the ill-fated expedition against Greece may have occurred between chapters 1 and 2 of Esther. Details on the Persian Empire are not given here because these are covered adequately in the books of Ezra, Nehemiah, and Esther, insofar as they related to the people of Israel and the plan of God, and these records are supplemented by the prophetic books of Haggai, Zechariah , and Malachi. Having mentioned “Greece,” Daniel’s revelation turned immediately to details of this third empire not given elsewhere in the Word of God.