Adam Clarke on Daniel 7:2

The four winds of the heaven strove upon the great sea - The idea of strife is taken here from the effects that must be produced, were the east, the west, the north, and the south winds to rise tempestuously, and meet on the surface of the sea. By the great sea, the Mediterranean is meant; and is so called to distinguish it from those lakes called seas by the Hebrews; such as the Sea of Galilee, Dead Sea, Sea of Tiberias, etc.; but even that may refer to Asia, the scene of all these contentions. This dream is the same in meaning, under different emblems, as that of Nebuchadnezzar's metallic image; but in Daniel's dream several circumstances are added. It is supposed that Daniel had this dream about forty-eight years after Nebuchadnezzar had the vision of the great image.