…he stopped, and as many times did his laughter break out afresh with the same violence as at first, whereat Don Quixote grew furious, above all when he heard him say mockingly, "Thou must know, friend Sancho, that of Heaven’s will I was born in this our iron age to revive in it the golden or age of gold; I am he for whom are reserved perils, mighty achievements, valiant deeds;" and here he went on repeating the words that Don Quixote uttered the first time they heard the awful strokes.
But Don Quixote, supported by his intrepid heart, leaped on Rocinante, and bracing his buckler on his arm, brought his pike to the slope, and said, "Friend Sancho, know that I by Heaven’s will have been born in this our iron age to revive revive in it the age of gold, or the golden as it is called; I am he for whom perils, mighty achievements, and valiant deeds are reserved; I am, I say again, he who is to revive the Knights of the Round Table, the Twelve of France and the Nine…
There are no more uses of "Iron Age" in the book.
Show samples from other sources
If she tried, Mae could get to at least a few of these events, but just when she was arranging some sort of itinerary, she saw something that obliterated all else: the Funky Arse Whole Circus would be on campus, on the lawn next to the Iron Age, at seven.
Dave Eggers -- The Circle
Then I’d remember Herodotus didn’t have a smartphone, because he had been dead since the Iron Age.