In Daniel 10:13, the angel's delay due to the prince of Persia explains why he now returns to fight — the same spiritual battle.

Daniel 8:5-8 depicts the goat (Greece) conquering the ram (Persia) — the historical fulfillment of the angel's coming battle.

Daniel 8:21 explicitly identifies the goat as the king of Greece — connecting the vision to the prince of Greece here.

Daniel 11:2-4 foretells the rise of Greece after Persia — the earthly events behind the angel's spiritual conflict.