Ammonius of Alexandria : Each nation has a guardian angel over them, so that they may not be harmed by the demons.… Therefore, the prince of the Greeks was also in the presence of God so that he himself heard the prophecies that were spoken concerning Alexander and those after him who would rule the world. — FRAGMENTS ON Daniel 10:20 Hippolytus of Rome : And so he says to him, "Do you know why I came to you? And now I will return to fight with the chief of the Persians, but I will proclaim to you what is written in the Scripture of truth, and there is no one who endures with me concerning these things except Michael your chief, and I left him there, for from the day you gave your face to be afflicted before your Lord God your petition was heard, and I myself was sent to fight with the chief of the Persians. For some plot happened to prevent me from coming to the people so that therefore in haste your request may be answered, I myself stood against him and I left Michael your chief there." [Daniel 10:12-14, 20-21] — Commentary on Daniel 4.40.3 Jerome : Verse 20. "'Dost thou know why I have come to thee? And now I will return to fight against the prince of the Persians.'" What he means is this: I have indeed come to teach thee of the things thou hast received in answer to prayer; but I am going to return once more to contend against the prince of the Persians in the sight of God, for he is unwilling that thy people be released from captivity. "For (Vulgate: Therefore) as I was coming away, the prince of the Greeks appeared and entered in (Vulgate: and came up)." He means, "I myself was departing from God's presence in order to announce to thee the events which are to befall thy people in the last days; and yet I am still not secure, since the prince of the Persians stands to plead against the granting of thy petitions and the acceptance of my advocacy on thy behalf. And behold, the prince of the Greeks, or Macedonians, had just come, and he entered in before God's presence to lodge accusation against the prince of the Medes and Persians, in order that the kingdom of the Macedonians might succeed in their place." Truly marvelous are the secret counsels of God, for it indeed came to pass that after the Jewish people had been freed from captivity, Alexander, king of the Macedonians, slew Darius and overthrew the kingdom of the Persians and Medes, so that the prince of the Greeks did overcome the prince of the Persians. — St. Jerome, Commentary on Daniel, CHAPTER TEN