Daniel 8:1 "In the third year of the reign of king Belshazzar a vision appeared unto me, even unto me Daniel, after that which appeared unto me at the first."
Daniel 8:2 "And I saw in a vision; and it came to pass, when I saw, that I was at Shushan in the palace, which is in the province of Elam; and I saw in a vision, and I was by the river of Ulai."
This vision comes shortly after the vision of the Beasts from Daniel Seven.
More understanding is given in each vision focusing less on the beginning and more on the end.
At this point Daniel is still in Babylon, yet the vision starts with the next kingdom.
Daniel 8:16 "And I heard a man's voice between the banks of Ulai, which called, and said, Gabriel, make this man to understand the vision."
During the vision Gabriel comes to explain.
Daniel 8:3 "Then I lifted up mine eyes, and saw, and, behold, there stood before the river a ram which had two horns"
Daniel 8:3 "And the two horns were high; but one was higher than the other, and the higher came up last."
In that night was Belshazzar the king of the Chaldeans slain. And Darius the Median took the kingdom, being about threescore and two years old. (Daniel 5:30-31)
Daniel 8:20 also names the kingdom by name.
Daniel 8:20 "The ram which thou sawest having two horns are the kings of Media and Persia."
Clearly we can see now the next kingdom after Babylon is Medo-Persia.
Daniel 8:4 "I saw the ram pushing westward, and northward, and southward; so that no beasts might stand before him, neither was there any that could deliver out of his hand; but he did according to his will, and became great."
Medo-Persia is shown as great.
Looking at the map you can see that the Media and Persia came from the east pushing west, north, and south conquering Babylon, Egypt and Lydia.
The animal sacrificed for our sins was a male sheep or ram which pointed to Jesus.
This ram comes from the east as did Jesus in Matthew 24:27 and destroys Babylon drying up the Euphrates Rev 16:12 just like we seen in Rev 14:8 and Rev 18:2.
Also in the sanctuary the lamb and high priest came from the east towards the west.
1843 Chart (By Charles Fitch and Apollos Hale)
1850 Chart (By Otis Nichols)