The "Bronze culture" of the Illyrians, ethno-tribal groups with distinct cultures, and art forms started to emerge from the cultures of the Copper Age. These Illyrian ethno-tribal areas were found in present-day Croatia, and Bosnia and Hercegovina. From the 7th Century BC, "iron" replaced bronze for tools and implements, only jewellery and art objects were still made out of bronze. The Celtic Hallstatt culture which bordered the Balkan region where the Illyrian ethno-tribal groups were living influenced them, but the Illyrian ethno-tribal groups formed their regional centers slightly differently.