The earliest archaeological evidence of bells dates back to more than 5000 years ago, from the 3rd millennium BC in Neolithic China. During this era, there is evidence of early forms of pottery cowbells, which were likely used to track goats, sheep, and cattle. The pottery bells were later replaced by metal bells. In West Asia, the first bells appeared in 1000 BC. The earliest metal bells, one found in the Taosi site, and four in the Erlitou site, are dated to about 2000 BC.