Bronze Age Europe dates to between about 2200 BC and 800 BC (although it goes on later in some areas). Copper working developed in southeast Europe thousands of years earlier. Bronze is copper plus tin, however, tin is a relatively rarer metal than copper, and the process of what they call "bronzization" spread across Europe after about 2200 BC, only after productive tin sources were located – mostly in western Europe -, and tin was regularly extracted and exported through well established trade