Traditionally bronze is copper and tin. When we talk of the "Bronze Age" we mean the period when copper from various sources was alloyed with tin primarily from Britain. They were the hottest trade commodities of their day. Adding zinc to copper made Brass, but as stated you can add all kinds of things to copper and these days there are a lot of different alloys.Brass and Bronze depends on who is talking about which! generally brass is dominantly a copper and zinc alloy, bronze generally has something else in it in place of the zinc or mixed in with the zinc. Aluminum bronze is just that, copper & aluminum, silicon bronze and leaded bronze are other good examples... However, there are some brass alloys that contain Tin or other metals in place of zinc.