When did the Celts began and end?

The Celts began to emerge as a distinct cultural group around the late Bronze Age, approximately 1200 BCE, and their influence spread across much of Europe during the Iron Age. The height of Celtic culture is often associated with the La Tène period, which lasted from about 450 BCE to the Roman conquest around 1 CE. However, Celtic identity persisted in various forms even after this period, particularly in regions like Ireland and Scotland, until the gradual assimilation into Roman and later Anglo-Saxon cultures. The Celtic culture as a dominant force effectively ended by the early Middle Ages, around 500 CE.