In what century did the widespread use of iron begin?

At the beginning of the 1st millennium BC. the time of the copper or the bronze age ends, then the time of the iron or, respectively, the iron age begins. Iron surpassed copper in strength, the main thing if, in addition to this, people finally learned how to work iron. And with this decisive turning point, progress began. Iron can be carbonaceous, it is steel, cast iron. And stainless, alloy steel. It has become the number one metal, so it is still. Thanks to him, the peoples of Eurasia left the communal system, came to a class one. Answer 10 c. BC.