Possible Clues:

• For example, an old king I overturned a long, long time ago
• It followed the Bronze era
• Press, mature? That was in the past
• When 23-Across first appeared?
• It started around 1100 B.C
• Period named for an element
• First millennium B.C., approximately
• When forging began
• Tool time?
• Forger's time