As for the ram that you saw with the two horns, these are the kings of Media and Persia.
The male goat is the king of Greece, and the great horn between its eyes is the first king.
References for Daniel 8:21
As for the horn that was broken, in place of which four others arose, four kingdoms shall arise from his nation, but not with his power.
References for Daniel 8:22
At the end of their rule, when the transgressions have reached their full measure, a king of bold countenance shall arise, skilled in intrigue.
He shall grow strong in power, shall cause fearful destruction, and shall succeed in what he does. He shall destroy the powerful and the people of the holy ones.
References for Daniel 8:24
By his cunning he shall make deceit prosper under his hand, and in his own mind he shall be great. Without warning he shall destroy many and shall even rise up against the Prince of princes. But he shall be broken, and not by human hands.
The vision of the evenings and the mornings that has been told is true. As for you, seal up the vision, for it refers to many days from now."
So I, Daniel, was overcome and lay sick for some days; then I arose and went about the king's business. But I was dismayed by the vision and did not understand it.