tech of the Iron Age
Eventually, three methods of hardening iron into steel came into common usage: watered or pattern-welded steel, wootz, and true damascus. - http://www.tf.uni-kiel.de/matwis/amat/def_en/articles/very_british/body_part1_damascene.html
Some Japanese swords have upwards of 36,000 layers and it is very difficult to discern the watering with the naked eye.
According to another legend, the common damascus blade was so flexible that a man could take the hilt in one hand and the point in the other and bend the blade in a circle around his body and when released, the blade would spring straight again.
The pattern welded blade went out of favor rapidly in Europe with the invention of the Catalan furnace in the 1300's in Spain.