The Iron Age is most accurately described as being dependent on the broad production of carbon steel as it is carbon steel rather than iron as such which, in most applications, is superior to bronze, particularly of weaponry and tool making. The first widespread use of iron was in Mesopotamia around 1200 BC and iron working was introduced to Europe in the late 11th century BC, probably from the Caucasus, and slowly spread northwards and westwards over the succeeding 500 years. By adding carbon in the form of charcoal and by quenching and tempering to improve strength, swords could be made that would not bend or break in use and so offered great benefits in warfare, however consistent use of these techniques was not necessarily universal and throughout the Iron Age and many blades were produced from unhardened iron which offered little improvement over bronze.