Analytical studies of copper minerals, smelting slags, and artifacts recovered from prehistoric sited in the Middle Danube basin of South-East Europe, dating to the fifth and fourth millennia BC, will be presented. Pure copper metals and alloys containing arsenic and tin have been excavated from Eneolithic Balkan sites. The recognition, identification, and analyses of the slags suggests the appearance of a metallurgical technology characterized by experimentation in the fifth millenium BC, and its subsequent evolution during the fourth millennium BC in South-East Europe.