I once read that Cappadocia, now in central Turkey, harbored the first production of iron ore. It was 1,500 BCE and they supposedly managed to keep it secret for 200 years, realizing its potential and the strategic advantage it gave to them.
Iron was known before as a metal of Divine descent. Archeologists have found a 2,500 BCE dagger made out of meteor iron from Egypt. Needless to say the metal revolutionized war fare by furnishing the sword and the carriage wheel axis. It became possible to control more people than before. More land was put under tillage because of the iron plow bill.