Iron production began way back in the Middle Bronze Age. The Hittites were the first to understand the process, and the vast availability of the raw material enabled bronze weapons to be replaced with iron ones. In Europe, the spread of ironwork is associated with the Celtic Expansion, being first introduced to Greeks around 1100 B.C.-1000 B.C. and reaching western and central Europe by 600 B.C. Iron was originally used mostly for functional purposes: weapons, tools, and architectural features. It is in the Middle Ages that iron became extensively used for decoration. Blacksmiths of this time were held in high regard. The ability to transform a seemingly coarse, hard material into something refined and beautiful was seen as a true gift.