The Age of Metallurgy, dawning about 1000 BE, gave rise to swords, spears and other implements of death to be used in cruel warfare.

Age of Barbarity c. 3120~2500 to c. 1000 BE
Age of Metallurgy c. 1000 to 200 BE
Age of Archery 200 BE to 660 GUE
Age of Powder 660 to 883 GUE
Age of Kaine 883 to 949 GUE

SOURCE(S): Zork Nemesis (Nino Ruffini's notes on the Design Documents)