23 Now since these things, spoken as they are with a mystical meaning, may seem to some hard to understand, we shall keep back nothing fitted to impart an intelligent apprehension of them to those who are possessed of a sound mind. He said, then, that a “lioness came up from the sea,” and by that he meant the kingdom of the Babylonians in the world, which also was the head of gold on the image. In saying that “it had wings as of an eagle,” he meant that Nebuchadnezzar the king was lifted up and was exalted against God. Then he says, “the wings thereof were plucked,” that is to say, his glory was destroyed; for he was driven out of his kingdom. And the words, “a man's heart was given to it, and it was made stand upon the feet as a man,” refer to the fact that he repented and recognised himself to be only a man, and gave the glory to God.
Source: The Antichrist (New Advent)