“And now will I shew thee the truth. Behold, there shall stand up yet three kings in Persia; and the fourth shall be far richer than they all: and by his strength through his riches he shall stir up all against the realm of Grecia.”
King James Version (KJV)
11:2 He - Xerxes was more potent than all the other three, because his father Darius had gathered an incredible mass for him, which he himself increased for six years together, before he made his expedition against Greece. There were more kings of Persia besides those four, but they had no concern with the people of God.