By what was the third universal empire symbolized?

Answer

"After this I beheld, and lo another, like a leopard, which bad upon the back of it four wings of a fowl; the
beast had also four heads; and dominion was given to it." Verse 6.
NOTES-If the wings of an eagle on the back of a lion denoted rapidity of movement in the
Babylonian, or Assyrian, Empire (see Hab. 1: 6-8), four wings on the leopard must denote unparalleled
celerity of movement in the Grecian Empire. This we find to be historically true.
"The rapidity of Alexander's conquests in Asia was marvelous: he burst like a torrent on the
expiring Persian Empire, and all opposition was useless. The gigantic armies collected to oppose him
melted like snow in the sunshine. The battles of Granicus, 334 BC., Issus in the following year, and Arbela
in 331 BC., settled the fate of the Persian Empire, and established the wide dominion of the Greeks .... . .
The Divine Program of the World's History," by H. Grattan Guinness, page 308.
"The beast had also four heads." The Grecian Empire maintained its unity but a short time after
the death of Alexander, which occurred in 323 BC. Within twenty two years after the close of his brilliant
career, or by 301 BC., the empire was divided among his four leading generals. Cassander took Macedonia
and Greece in the west; Lysimachus had Thrace and the parts of Asia on the Hellespont and Bosporus in
the north; Ptolemy received Egypt, Lydia, Arabia, Palestine, and Coele-Syria in the south; and Seleucus
had all the rest of Alexander's dominions in the east.