Alexander the Great was that "notable" horn, which was broken at his apex of power & his kingdom was divided between his 4 successors.
And as I was considering, behold,
an he goat came from the west on the face of the whole earth, and touched not the ground:
and the goat had a notable horn between his eyes.
Therefore the he goat waxed very great:
and when he was strong, the great horn was broken;
and for it came up four notable ones toward the four winds of heaven.
Daniel 8:5,8
It is said that Alexander wept when he thought there were no more worlds to conquer.
And the rough goat is the king of Grecia:
and the great horn that is between his eyes is the first king.
Daniel 8:21