It seemed to some that Ireland was about to be overrun and made subject to the Vikings
- the view of the Irish émigré sources that lie behind the Annales Bertiniani for 847 : ‘After
they had been for many years under attack from the Vikings, the Irish were made
tributaries to them; the Vikings have possessed themselves without opposition of all the
islands round about and have settled them.’
The Irish provincial kings, who spent their energies on their own power struggles,
slowly turned on the Vikings (Ó Corráin 1979 : 283 – 323 ). In 845 Niall Caille, king of
Tara and king of the northern Uí Néill, defeated them in battle in Donegal. In 848 ,
Mael Sechnaill, king of Tara since 846 , defeated the Vikings near Skreen (Co. Meath),
and killed 700 of them. In the same year, Ólchobar mac Cináeda, king of Munster, and
Lorccán mac Cellaig, king of Leinster, joined forces and defeated the Vikings in a major
battle near Castledermot, Co. Kildare.
These victories lie behind an important embassy sent to Charles the Bald, the
Frankish emperor, in 848 and an exaggerated report in the Annales Bertiniani: ‘The Irish
attacked the Vikings and with the help of our Lord Jesus Christ they were victorious and
drove them out of their territory.’
By the second half of the ninth century the Vikings were a familiar element in Irish
life and militarily impressive (Ó Corráin 1987 : 287 – 93 ). They had small permanent
settlements and had become part of the country’s politics. The Irish aristocracy found
them useful as allies and mercenaries. From this point Viking–Irish alliances become
commonplace, and no matter for reproach. The annalists report frequent Irish–Viking
alliances in the ninth century and there was intermarriage at the very highest levels of
Irish society.
Relatively unsuccessful as conquerors in Ireland, the Vikings turned to Scotland,
with dramatic results. The Irish annals report:
Amlaíb and Auisle [the kings of Dublin] went to Fortriu with the Vikings of
Ireland and Scotland and they ravaged the whole of Pictland and took their
hostages.The Dublin dynasty, commanding the Viking forces of Ireland and of their original
settlement in Scotland, invaded southern Pictland, then plundered the whole of
Pictland, and took hostages, as overkings, to enforce their authority. This leaves no room
for independent kings: Constantine I (r. 862 – 76 ), called ‘rex Pictorum’, will have given
hostages with the rest. And they placed Pictland (southern and eastern Scotland) under
tribute. They returned to Dublin, and for the next four years there is a detailed account
of their activities – enough to show that Dublin was their base of operations and that the
Irish did not make things easy for them. There was a successful attack on Dublin itself in
867 and a major defeat in battle in 868 , in which Carlus, son of Amlaíb, fell.
It is not surprising, then, that in 870 – 1 the Dublin leadership turned again to
Scotland, now to the south-west British kingdom of Strathclyde:
[ 870 ] The siege of Dumbarton by the Nordmanni i.e. Amlaíb and Ímar the two
kings of the Nordmanni besieged that fortress and at the end of four months they
destroyed the fortress and plundered it. [ 871 ] Amlaíb and Ímar came back to
Dublin from Scotland with 200 ships and they brought with them in captivity
to Ireland a great prey of Angles, Britons and Picts.–– Donnchadh Ó Corráin––