Historians estimate that Ireland was first settled by humans at a relatively late stage in European terms – about 10,000 years ago. Around 4000 BC it is estimated that the first farmers arrived in Ireland. Farming marked the arrival of the new Stone Age. Around 300BC, Iron Age warriors known as the Celts came to Ireland from mainland Europe. The Celts had a huge influence on Ireland. Many famous Irish myths stem from stories about Celtic warriors. The current first official language of the Republic of Ireland, Irish (or Gaeilge) stems from Celtic language.