 Before Cyrus and his army crossed the Aras River to battle with the Armenians, he installed his son Cambyses II as king in case he should not return from battle.However, once Cyrus had crossed the Aras River, he had a vision in which Darius had wings atop his shoulders and stood upon the confines of Europe and Asia (the known world).When Cyrus awoke from the dream, he inferred it as a great danger to the future security of the empire, as it meant that Darius would one day rule the whole world.