The Vikings invaded the territory around Dublin (Dubh Linn; "Black Pool") in the ninth century, establishing the Norse Kingdom of Dublin. This corresponded to most of present-day County Dublin. Norse Rulers of Dublin were often co-kings, and occasionally also Kings of Jorvik in what is now England. The region was known to the Vikings as Dyflin, pronounced "dyoov-lin" (in either Old Norse or Modern Norwegian). The English later took Old Irish "Dubh Linn" and collapsed it to the modern "Dublin". Manx still uses "Divlyn".

In 988, High King Mael Seachlainn II led the initial Irish conquest of the Norse Kingdom of Dublin, giving the place its modern name in Irish—Baile Átha Cliath, meaning "Town at the Hurdle Ford." Thus, the founding of Dublin is counted from the year 988, notwithstanding a village has existed on the site of Dublin since before the Roman occupation of Great Britain nearly a thousand years earlier.

Mael Seachlainn II was dethroned by Brian Boru, 1002-1014, and the Norse kept fighting back—so the Irish conquest of Dublin was never complete. Irish dominance of Dublin did take hold in the middle of the eleventh century, under the kings of Leinster; but the city still had a Norse king until the Norman invasion of 1171, and native Ireland itself was in the throes of the regnal wars over the high kingship since the death of Mael Seachlainn II in 1022. Though the last Norse king of Dublin was killed by the Normans in 1171, the population of the city retained their distinctiveness based on their origins for some further generations.

Norse Kings

Ruler	Reign	Notes
Thorgest	839 - 845	drowned in Lough Owel
Amlaíb Conung	853–873	brother of Ímar and Auisle
Ímar	856–873
Auisle	853–867
Eystein Olafsson	873–875
Halfdan	873/875–877
Bard	875/877–881
Mac Auisle	881–883
Eoloir Jarnknesson	?–?
Sichfrith Ivarsson	883?–888
Sigtrygg (Sitric) Ivarsson	888–893
Sichfrith Jarl	893–894
Sigtrygg (Sitric) Ivarsson	894–896
Ivar	893–902
Dublin abandoned by the Norse from 902 to 917.
Sihtric ua Ímair	917–921	defeated Niall Glundub; also king of Jórvík
Gofraid ua Ímair	921–934	grandson of Ímar
Olaf III Guthfrithson	934–940	son of Gofraid ua Ímair
Blácaire mac Gofrith	940 - 945
Sigtrygg (Sitric)	941–943
Amlaíb Cuarán	945 - 947
Blácaire mac Gofrith	947 - 948	restored
Gofraid mac Sitriuc	948 - 951
Amlaíb Cuarán	952–980	restored
Glúniairn	980–989
Sigtrygg (Sitric) Silkbeard Olafsson	989–1036
Echmarcach mac Ragnaill	1036–1038
Ivar Haraldsson	1038–1046
Echmarcach mac Ragnaill	1046–1052
Murchad mac Diarmata mac Mael na mBo	1052–1070
Diarmait mac Mail na mBo	1070–1072
Domnall mac Murchada mac Diarmata	1070–1072
Gofraid mac Amlaib mac Ragnaill	1070–1072
Toirdelbach Ua Briain	1072–1074?
Muirchertach Ua Briain	1074–1086
Enna mac Diarmata mac Mael na mBo	1086–1089
Donnchad mac Domnail Remair mac Mael na mBo	1086–1089
Godred Crovan	after1091–1094
Domnall mac Muirchertaig ua Briain	c.1094–1118
Donnchad mac Murchada mac Diarmata	????–1115
Diarmat mac Enna	1115–1117
Enna mac Donnchada mac Murchada	1118–1126
Conchobair mac Tiorrdelbach Ua Conchobair	1126–1127
Thorkell	fl.1133
Conchobair Ua Briain	1141–1142
Ottar	1142–1148
Ragnall Thorgillsson	11??–1146
Brotar Thorgillsson	1146–1160
Hasculf Thorgillsson	1160–1171

(N.B. "Sitric" is the Irish variant of Norwegian "Sigtrygg")

Notes