Celtic Ireland, about 1500 years ago, was a very different country from today. The people were known as Celts. They were great warriors, metal-workers and farmers.
At that time, there were no towns or roads and the whole country was covered in forest. The Celts lived together in tribes and each of these tribes had its own king. Wealth was measured by the animals you owned and the goods you could trade.
In those early days, Christianity wasn't widely known in Ireland. Important men called 'druids' guided the people: they were wise and learned men, almost as important as the kings.