After Finbarr`s death the community continued to grow but in 820 AD the Vikings raided the abbey and the settlement nearby. They burned the buildings and plundered (stole) the treasures of the monks such as chalices, crosses, and brooches. The Round Tower which was built by the monks on the site did little to protect the monks from these attacks. Over the next forty years it is said that different bands of Vikings attacked the monastery eleven times in total.

Who were the Vikings?

The Vikings came from the craggy fjords and the icy waters of northern Europe, from Norway, Sweden and Denmark. Life was hard for them ,as the soil was poor for growing crops. Therefore they looked to the sea for everything, for fish, for the promise of new lands and gold and slaves from across the horizon. They were also skilled as carpenters and they built the best wooden boats to be found anywhere in the world at that time. These were known as 'longboats'.

.Some Vikings decided to settle in Cork so they created their own town on an island in the River Lee. They built their wooden huts across the river from the monks settlement on the site that is presently occupied by the Beamish and Crawford Brewery. They began to trade hides and fish with the local clans and with the other Viking settlements in Ireland and abroad. Over the next few hundred years these Vikings learned to speak the Irish language and dress like their Irish neighbours.They gradually became the same as the Irish.