with the Irish kings, but the newcomers were victorious. Sitric repossessed Dublin, and
Ragnall led his troops back to northern England to campaigns that made him king of
York and ruler of Northumbria. Henceforth, Dublin and York were ruled by a single
dynasty and this brought about dramatic change in Ireland, in trade, urbanisation and in
the resources of its kings. Dublin became a sea-kingdom, the centre of far-flung eco-
nomic and political interests. It had real power and influence in the Irish Sea, Scotland
and northern England – resources that made it much more formidable than the limited
assets in land and manpower it held in Ireland.
Dublin aimed to make strategic conquests. There was an intense campaign in
eastern Ulster, 921 – 7 and again later, led by Dublin and using large fleets, to create a
Scandinavian kingdom like that on the other side of the Irish Sea, and to control north–
south transit and trade (Smyth 1975 – 9 vol. 2 : 23 ). This was foiled by Muirchertach mac
Néill, king of the northern Uí Néill, who was later defeated and slain by the Dubliners.
Amlaíb, king of Dublin, led the opponents of King Athelstan at the great battle of
Brunanburh: at stake was the kingship of England. Athelstan won a decisive victory,
but Amlaíb escaped to Dublin in 938. On Athelstan’s death in October 939 Amlaíb
sailed for England, reached York before the year’s end and was made king by the
Northumbrians. He followed this with a campaign south of the Humber. The result
was a negotiated settlement with Edmund, Athelstan’s successor, by which Amlaíb was
recognised as king of York and ruler of Danish Mercia – almost half the kingdom of
England. He died in 941.
York was soon lost by his successor, Amlaíb Cuarán, who returned to Ireland in 945
to fierce Irish–Viking warfare. In 944 Congalach, king of Brega, and the king of Leinster
had united against Dublin in a pincer movement and sacked the city with a new
ferocity: ‘The destruction brought upon it was this: its houses, house-enclosures, its
ships and its other structures were burned; its women, boys and common folk were
enslaved; its men and its warriors were killed; it was altogether destroyed, from four
persons to one, by killing and drowning, burning and capture, apart from a small
number that fled in a few ships and reached Dalkey.’ Congalach attacked Dublin again
in 948 , killed its ruler and 1 , 600 of its troops were either killed or taken prisoner.
Amlaíb Cuarán tried his luck in England again and he held the kingship of York from
about 948 until he was driven out in 953. He returned to Dublin.
Though a powerful king of Dublin, Amlaíb Cuarán fatally overreached himself. He
battled with the major Irish kings: he defeated and killed the king of Leinster in battle
near Athy and attacked Meath. In 980 he invaded Meath but Mael Sechnaill mac
Domnaill, its king, inflicted a crushing defeat (the annalist calls it ‘a red slaughter’) on
him at the battle of Tara. His long-planned attempt at conquest failed disastrously, and
his signal defeat decisively broke the power of Dublin. Mael Sechnaill besieged the city
and it met his terms: the release of all Irish hostages, the handing over of treasure and
the freeing of all Uí Néill lands from tribute. Mael Sechnaill further proclaimed the
liberty of all Irish slaves in Viking territory – that, says the annalist, was ‘the Babylonian
captivity of Ireland, second only to the captivity of hell’. Amlaíb Cuarán went to Iona as
a penitent, and died there in religious retirement.
This marked the end of Viking military power in Ireland. All the Viking cities –
Dublin, Limerick, Waterford, Cork and Wexford – were henceforth ruled directly or
indirectly by Irish kings. Dublin and Waterford were often autonomous, though they
were sometimes ruled directly. Limerick was under the Uí Briain kings of Munster: they
–– Donnchadh Ó Corráin––