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Gold, silver, bronze, iron: Greece, Persia and the Book of Daniel all count the ages of the world in metals, India counts four yugas, and the Norse and Maya see whole worlds destroyed and remade.
Many ancient peoples believed the world had been better once and has been getting worse. Hesiod lists a golden race of humans who lived like gods, followed by silver, bronze, heroes and our own iron age. Ovid retells it. The Persian Bahman Yasht shows Zoroaster a tree with branches of gold, silver, steel and mixed iron, and the Book of Daniel describes a statue with a head of gold, chest of silver, belly of brass and legs of iron. India's Laws of Manu describe four ages in which justice loses a leg in each.
Other traditions add that whole worlds are destroyed and replaced. Plato's Egyptian priest says there have been many destructions of mankind by fire and water. The Persian Bundahishn measures time in 12,000-year blocks. The Norse Voluspa sees the earth sink in the sea and rise again green. The Maya Popol Vuh tells of earlier attempts at people that the gods destroyed. The versions are quoted below from public-domain translations.
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Greek
First of all the deathless gods who dwell on Olympus made a golden race of mortal men who lived in the time of Cronos when he was reigning in heaven. And they lived like gods without sorrow of heart, remote and free from toil and grief
Same and different: The classic list: gold, silver, bronze, heroes, iron; unlike the others it breaks the metal decline with an age of heroes.
Roman
The Golden Age was first founded, which, without any avenger, of its own accord, without laws, practised both faith and rectitude.
Same and different: Same metal ages as Hesiod (gold, silver, bronze, iron), without the heroes; the iron age ends in the flood of Deucalion.
Hebrew Bible
This image’s head was of fine gold, his breast and his arms of silver, his belly and his thighs of brass, His legs of iron, his feet part of iron and part of clay.
Same and different: Same descending metals; different: they stand for four empires, not races of humans, and the series ends with God's kingdom, a stone that smashes the statue.
Zoroastrian (Persian)
he beheld the root of a tree, on which were four branches, one golden, one of silver, one of steel, and one was mixed up with iron.
Same and different: Almost the same as Daniel's statue, including the last metal 'mixed up with iron'; the four branches are four coming periods of history.
Zoroastrian (Persian)
Time was for twelve thousand years; and it says in revelation, that three thousand years was the duration of the spiritual state, where the creatures were unthinking, unmoving, and intangible
Same and different: Same idea of fixed world ages; different: they are four blocks of 3,000 years in a war between good and evil that ends in renewal.
Hindu law code
The Manvantaras, the creations and destructions (of the world, are) numberless; sporting, as it were, Brahman repeats this again and again. In the Krita age Dharma is four-footed and entire, and (so is) Truth
Same and different: Same golden first age followed by decline (the Krita, Treta, Dvapara and Kali yugas); different: no metals, and the cycle repeats endlessly.
Greek (Plato)
the earth gave them fruits in abundance, which grew on trees and shrubs unbidden, and were not planted by the hand of man. And they dwelt naked, and mostly in the open air, for the temperature of their seasons was mild
Same and different: Same golden age under Cronos as Hesiod; different: Plato makes it one half of a cosmic cycle in which the universe turns one way and then reverses.
Greek, about Egypt
There have been, and will be again, many destructions of mankind arising out of many causes; the greatest have been brought about by the agencies of fire and water, and other lesser ones by innumerable other causes.
Same and different: Same repeated destruction of humanity as the yugas and the Maya creations, and it explicitly links fire and flood; this is the passage that leads into the Atlantis story.
Norse
The sun turns black, earth sinks in the sea, The hot stars down from heaven are whirled ... Now do I see the earth anew Rise all green from the waves again
Same and different: Same end of a world by fire and water and a fresh start; different: there are not several ages, just this world and the renewed one after Ragnarok.
K'iche' Maya
To supply the deficiency the divine beings resolved to create mannikins carved out of wood. But these soon incurred the displeasure of the gods, who, irritated by their lack of reverence, resolved to destroy them.
Same and different: Same series of earlier humanities destroyed by the gods (compare the Aztec Legend of the Suns with its four destroyed worlds); different: it is a sequence of improving drafts, ending with people made of maize, not a decline.
The metal ages are the clearest case of borrowing. Hesiod's golden, silver, bronze and iron races, Daniel's statue and the Persian tree of four metal branches are too alike to be chance, and most scholars think they share a source in the ancient Near East or Iran, spreading across the Persian Empire and the Greek world; which came first is still argued, since the Persian text survives only in late copies. Ovid simply took Hesiod's scheme. India's four yugas and the Persian 12,000 years are separate systems with the same logic of decline. Beyond these links, the general idea of a better past has a common human explanation: every generation tends to think the world was better before, and early farmers really did remember a time of less toil. Cycles of destruction and renewal may also reflect real catastrophes (floods, eruptions, droughts) and the observed cycles of the sky. The Maya and Aztec world ages developed independently in the Americas and are tied to their own calendars, which shows the idea can arise on its own.
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