Yet, it was entirely unknown what gave steel its valuable properties, and for centuries the techniques for making high quality steel were closely held, almost alchemical, secrets. Clearly, iron was its major component, but a myriad of other minor additions were found empirically, and even more mysterious treatments were evolved for cooling the red hot object to room temperature - unlikely manufacturing processes such as adding mixtures of blood, and aging times which depended on the phase of the moon, for example. B.C. Iron was known before this time, but Maddin suggests that it was the discovery of how to make steel that led to the shift. Maddin's earliest example of martensite comes from an excavation in 1976. He says the analysis shows a pretty sophisticated manipulation of iron into steel.
Arrow indicates flake shown in the next figure.
11th century B.C. knife excavated from a tomb in Idalion, Cyprus. I'm guessing the stiated lines are martensitic twins. As when a man who works as a blacksmith plunges a screaming great axe blade or plane into cold water, treating it for temper, since this is the way steel is made strong, even so Cyclops' eye sizzles about the beam of the olive. In the 19th century there were great advances in chemical analysis, and metallurgists had faith that the reasons why steels were different would soon be known through determination of differences in chemical composition. However, these hopes were soon dashed, as it was often found that various steel alloys with very similar compositions could have vastly dissimilar mechanical properties.