In the period from the fifth and sixth centuries onwards, Scotland was divided into four kingdoms: Dalriada, Pictavia, Gododdin (Lothian), and Strathclyde. Strathclyde's capital was at Dumbarton Rock, or Alt Cluid, on the Firth of Clyde. Dumbarton was attacked by Vikings in 870 AD, and seems to have ended its role as an independent kingdom shortly afterwards, around 900.
The Vikings had laid siege to Dumbarton for four months in 870, eventually defeating the inhabitants when they cut off their water supply. The Norse king Olaf returned to the Viking city of Dublin in 871, with two hundred ships full of slaves and looted treasures. Olaf came to an agreement with Constantine I, king of Scots, and Arthgal f Dyfnwal1, king of Strathclyde, was executed. Rhun f Arthgal, brother-in-law of Constantine, became king of Strathclyde, apparently as a client or sub-king of Constantine.
Rhun was to die c. 878, possibly in the same battle as Constantine, who was killed fighting the Norse. He was succeeded by Eochaid f Rhun, who allied himself with Giric f Dungal of the Scots. The two reigned jointly over Alba and Strathclyde until 889, when they were expelled, effectively ending Strathclyde's status as an independent state, c. 890. Following their expulsion, Donald f Constantine became king of Strathclyde. This marked the merging of the kingships of the Scots from Dalriada and the Britons of Strathclyde. Strathclyde kept some independence, but its kingdom was essentially one subject to Scottish rule.
Strathclyde's history beyond this point is at best sketchy, although there is evidence which suggests that some of the Strathclyde nobility fled to Gwynedd in north Wales. Lands previously belonging to Strathclyde seem to have become a sub-kingdom under Scottish control.
The first source of evidence which refers to the exodus to Wales c. 890 is the Welsh Chronicle of the Princes:
It remains uncertain whether Eochaid travelled to Gwynedd with his people, since the date of his death is unknown, but other evidence supports and corroborates the possibility of a small group of Strathclyde nobility travelling to Gwynedd c. 890.
Firstly, the migration would explain the growth of the cult of St Kentigern in north Wales. Jocelin's Vita Kentigerni tells a strange tale about a period of exile in Gwynedd for St Kentigern. There are dedications to him at St Asaphs and elsewhere in north Wales, and also many dedications in Cumbria.
Secondly, Glasgow remained obscure as the cult centre of St Kentigern, until it was revived by Earl David between 1113 and 1124. Perhaps this obscurity dated back to 890 and later years, although this may be ambitious, and is not borne out by the Inquisitio David. Jocelin's Vita Kentigerni, however, might well date back to the eighth and ninth centuries in its earliest sections, which could perhaps have been written by a Glasgow scriptorium, active until the later ninth century, and folding with the Strathclyde exodus.
A third clue that would back up the migration theory is that the pedigree of Rhun f Arthgal has been preserved in Welsh lore. Other traditions relating to the 'Men of the North' may also have some bearing, and the 'Welsh' poetry of Y Gododdin might have travelled to Wales with the Strathclyde exiles.
Following the flight to Gwynedd, the Strathclyde kings seem to have been client or sub-kings of the kings of Scots. Donald f Aed, for instance, was definitely part of the royal Scottish dynasty, and some other Strathclyde kings may also have been. Strathclyde's independence effectively came to an end with the death of Ywain (Owen) the Bald, who died in 1018, when the dynasty of Kenneth f Alpin began to rule the region.
The influence of the Norse in Strathclyde during the period from 870 onwards cannot be ignored. Five "hogback" house-shaped gravestones of Norse design are to be found at Govan Parish Church in modern-day Glasgow, a site that had religious importance for the Strathclyde kings. A road leads from the churchyard to Doomster Hill, a large earthen mound used as an assembly place, in a manner similar to that found at Tynwald in the Isle of Man, where, the church of St John is linked to the Manx parliament hill by a straight processional route. The links to the Norse kings of Man of the ninth and tenth centuries suggest a strong Norse influence in Strathclyde at that time.
The name Strathclyde was revived during local government reorganisation in the mid 1970s, with a Regional Council area called Strathclyde being created, with the city of Glasgow at its heart. The regional tier of government was abolished in 1995 and its responsibilities merged with the District Councils to create Unitary Authorities (of which there are 32 in Scotland).
Strathclyde Regional Council was by far the largest of the Scottish Regional Authorities, with a population in excess of 2 million and an area stretching from the Highlands to the Southern Uplands. The politics of the region were by in large dominated by the Labour Party.
Strathclyde Regional Council was replaced by 12 Unitary Authorities, they being:
See also: Strathclyde University.