Possible Clues:

• When blacksmithing began
• Period in human history after bronze was supplanted in toolmaking
• First millennium B.C., roughly
• Period of cultural development, beginning in Europe around the eighth century B.C.
• When bronze was supplanted in toolmaking
• When steel was first forged
• Period in ancient history
• Heavy metal time?
• Period forged in history books?
• Third and last epoch of the three divisions of European prehistory