 The long @-@ standing traditional view , once widely accepted , is that Celtic language , <unk> script and culture were brought to Ireland by waves of invading or migrating Celts from mainland Europe . This theory draws on the <unk> <unk> <unk> , a medieval Christian pseudo @-@ history of Ireland along with the presence of Celtic culture , language and artefacts found in Ireland such as Celtic bronze <unk> , shields , <unk> and other finely crafted Celtic associated possessions . The theory holds that there were four separate Celtic invasions of Ireland . The <unk> were said to be the first , followed by the <unk> from northern Gaul and Britain . Later , <unk> tribes from <unk> ( present @-@ day Brittany ) were said to have invaded Ireland and Britain more or less simultaneously . Lastly , the <unk> ( <unk> ) were said to have reached Ireland from either northern Iberia or southern Gaul . It was claimed that a second wave named the <unk> , belonging to the <unk> people of northern Gaul , began arriving about the sixth century BC . They were said to have given their name to the island . 
