As Scandinavia was becoming increasingly over-populated the Vikings found a need to discover new land and create settlements, Ireland being one of them. They had also settled in Scotland and, like Ireland, started to settle with the local population. In Scotland these people became known as The Gallowglasses and would later arrive in Ireland as hired mercenaries

In 795 the first Vikings in Ireland landed on the Irish shores with their Viking ships attacking their first Irish monastery in Rathlin Island located near Co Antrim. Attacks on Ireland remained very few over the next 30–40 years with attacks taking place approximately once a year. It is known the Irish resisted these attacks on a few occasions and in 811 seen the Ulaidh slaughter the Vikings attempting to raid Ulster. In 823 the Vikings attacked and pillaged Bangor and repeating these attacks again the next year.

At first the Vikings in Ireland stayed within 20 miles of the coast unsure what lay ahead inland keeping their attacks on coastal Irish monasteries and made more permanent settlements with their first “wintering over” located at Lough Neagh during 840-841. Then between 841-842 settlements were established in Dublin, named Dubhlinn, and then Cork and Waterford which was named Vadrefjord.

849-852 saw the arrival of new Vikings, the Danes who were named by the Irish as the dark foreigners. The more settled Vikings in Ireland, the Norse named the fair foreigners, quickly went to battle with the Danes in the Irish Sea and Strangford Lough.

In 860 the Vikings of Waterford attacked the King of Israige but were slaughtered and attacks on the Vikings in Ireland increased. In 866 the settlement longphort was destroyed and the King of Northern Uí Néill managed to rid the Vikings from Ulster. Connachtmen in 887 slaughtered the Vikings of Limerick and in 892 Wexford, Waterford and St Mullins Vikings were also slaughtered.

For the next ten years the Vikings focused their attacks elsewhere in Europe but with fewer opportunities they returned to Ireland in 914 as much larger force with Vikings of Britain joining their attacks in Viking ships.

Ulster became vulnerable with the death of Niall Glúndubh in 919 after which the Vikings raided Tír Conaill and attacked Armagh again. Over 32 ships entered Lough Foyle and in 924 they returned to Lough Erne to set up their fleets. Once again Ireland became enslaved by the overwhelming power of the Vikings which would not last long.

Irish monasteries lacked defences from Viking attacks. A new form of building was constructed known as ‘roundtowers’ built by stone and proved strong in defence. It had a unique feature of having only one entrance to the roundtower that was at least 10ft from the ground so a ladder was needed to gain entry. Roundtowers can still be seen today dotted around the Irish countryside and their unique features still standing strong.

An Axe used by the Irish Niall Glúndubh’s son, Muircertach, took revenge in setting up attacks from his base, Grianan of Aileach in Co Donegal, which still stands today and is a perfect example of round forts in Ireland. Muircertach won victories over the Vikings in battles such in 926 on Strangford Lough and in Dublin in 939. He went onto the Scottish Isles with his Ulster fleet attacking Viking settlements in 941 but died in Combat in 943.

Brian Boru of Dál Cais became King of Munster and who was first to call himself High King of All Ireland after his brother was killed during battle. With the help of the Uí Néill, Brian Boru slaughtered the Vikings of Dublin and was seen as the High King in 1002.

One of the main reasons the Vikings failed to take full control of the island is that they made the mistake of getting involved with Ireland’s internal affairs which seen many clans battle with each other for control of different regions. The Vikings joined forces with the clan of Leicester to defeat Brian Boru and called on forces to come to Ireland from all over the Viking Kingdom.

On Good Friday 1014 the Viking fleet arrived in Dublin bay to battle with Brian Boru. Brian’s Army consisted of his Munster army and the Limerick and Waterford Vikings, who had joined forces with Brian Boru. Although Brian was killed, at age 70, as he prayed in his tent for victory the Vikings were driven back to the Viking ships with many being slaughtered on the coast of Clontarf which would see Viking power in Ireland lost forever.

Although the Viking power was taken away it is well-known they helped the Irish progress in terms of technology in building warships, weapons and battle tactics and also built the first towns such as Dublin, Cork and Waterford. Many Vikings still lived on in Ireland and married into Irish families which would help shape many future generations.

With the invasion of the Vikings and internal disputes the Church in Ireland was reduced and its influence abroad was dramatically smaller than previous years. Rome was quite worried that Ireland was losing touch with Christianity and the country would need reform and discipline yet again. Malachi of Armagh, aged 29, would be appointed Bishop of Down and Connor in the North East.