The Kings Of Persia.
“And now I will show you the truth. Behold there will stand up yet three kings in Persia, and the fourth will be far richer than all of them, and when he has established himself strongly through his riches he will stir up all against the realm of Greece.”
‘And now I will show you the truth.' That is the truth as indelibly inscribed in the writing of truth (Daniel 10:21), which must therefore come about.
The fourth king, richer than all, who becomes excessively rich and powerful, and stirs up all (either all the resources of the empire, or all peoples from his empire) against Greece is undoubtedly Xerxes. ‘There will stand up' suggests that Cyrus the current king was not in mind. Thus the four would be Cambyses, Smerdis, Darius Hystapsis and Xerxes.
The purpose of the verse is to bring out the growth of the Persian empire to its maximum point and the result that followed, the first major invasion of Greece. It is really preparatory to the details given of the Greek empire. There is no intention of outlining Persian history. This is not simply an exercise in foretelling the future, it is depicting the fulfilment of God's purposes. The idea is to show the steps of growth up to the fourth massive empire previously mentioned, but not to depict all the details. Certainly it is patterned on the previous visions. That is why only four kings are mentioned and Cyrus, as the reigning king, is omitted. (Had he been needed in order to make up four he would have been included). The fourth king, like the fourth empire, is the potent one from a world point of view.
Daniel is very much aware that he could not (in his schema) be the ‘fifth' king, for that would make him the covenant king. In the same way in the previous visions there could not be five empires, until, that is, the arrival of the covenant empire, for five is the number of covenant. Xerxes had to be the fourth king, however the number was to be obtained. He was from the world's viewpoint ‘ the king' as far as Persia was concerned. Only he was powerful enough to instigate the invasion of Greece.
His failure to mention any Persian king after Xerxes was not due to lack of knowledge but the requirements of his schema. Kings who followed him were irrelevant for Xerxes had made the move that would introduce the Greek empire. He was ‘the fourth king' who included all that followed.
Xerxes invaded Greece in 480 BC, with a huge army, but he suffered defeat and never recovered, for after he had subdued virtually all of Greece down to the Isthmus of Corinth, including the reduction to ashes of the city of Athens, his navy was thoroughly worsted by the united Greek fleet at the Battle of Salamis in 480 BC. He himself retreated leaving his general Mardonius to see to affairs, and he was crushed in the following year by the allied forces of the Greeks at the battle of Plataea. All subsequent attempts to crush Greece also failed. In Xerxes was summed up all Persia's future against Greece.