Changes

Iron likely helped forge many empires that developed in the 1st millennium BCE, where the control of production now gave these states military advantage (Figure 1). While the incentives of gaining military advantage helped spread ferrous technologies, including iron and steel making, many secondary effects of this innovation began to develop. First, iron and steel produced not only better swords, spears, and axes, but cutting tools, hammers, saws, and other implements all benefited. This now made it possible to radically transform the landscape. New technologies soon emerged after the innovation of ferrous technologies, including the development of aqueducts and qanats. These water-based technologies allowed areas that were relatively dry to be more easily irrigated through major irrigation works. Iron was also more prevalent than other metals, which meant that many societies were able to benefit from this development. Large forested areas were cleared, terracing became easier, and fuel needed for iron making and other operations were more easily gathered as wood could be cut easier. In effect, the stage was set for new areas to be settled and for infrastructure expansion, including water provisioning, that allowed cities to grow.

==Later Developments==