Copper contents of Bronze Age slags were compared with slags dated 1520; the Bronze Age process allowed a higher enrichment of bronze with copper than the latter ones. It was determined that a two-stage process was used; in the first stage the enrichment began under high temperature and reducing furnace conditions, whereas in the second stage the enrichment of copper matte was carried out at lower temperature under oxidizing conditions. This enrichment process was far superior to any method used in the Middle Ages. See also 20-1020. -- AATA