The Iron Age

Zeus made yet a fifth generation of men after the Dark Ages, and with it began the Age of Iron. Men never rest from labor and sorrow by day, and from perishing by night. Modesty, truth, and faith leave the earth, and in their place come tricks, plots, traps, violence, and unbridled love of profit. The ground, which had been common possession, is now neatly marked with boundary-lines. Men demand of the fields, not only the sustenance they provide with their surface, but also what is in the very bowels of the earth, bringing to light the wealth buried and hidden away by the gods.
Not only hard iron came with this age; but also gold, which is even worse than iron. And with both war came, and so men found it natural to live on plunder. The guest cannot trust his host, and affection among brothers became rare. The husband started longing for the death of his wife, and she for the death of her husband. Piety was vanquished, and the last of the immortals left the earth to dwell in Olympus.
Zeus will destroy this race of mortal men too.
Prophecy has that the fathers will not agree with their sons, and brothers will kill one another. Might shall make right, so that one man may sack another man's city. There will be no merit for the man who keeps his word, or for the just, or for the good; rather, men will praise the evil-doer and admire his audacity and violent dealings. Strength will be right, and respect will vanish as an empty word. Peace being banished, the Muses will depart; therefore they will lead a life in ugliness. The wicked will hurt the worthy, speaking false words against them; therefore will envy walk along with them. The gods will forsake mortal men, letting bitter sorrows fall upon them; and being defenseless like children in the wilderness, they will not find any help against all evil they themselves created.
The advent of Alexander however, gave hope to men that this destruction could be averted, that this doom might never come to pass