The ancient craft of processing metals flourished considerably during the years when the Greek popular arts were at their peak, and important production centers were established in Epirus (Ioannina), Macedonia (Thessaloniki) and the Peloponnese (Stemnitsa). Metalware objects were made of copper, iron, bronze and lead and were used mainly for agricultural implements but also for ecclesiastical and household utensils. The great demand for metal utensils led to a division of labor and the specialization of craftsmen according to the type of metal they worked and the objects they made.