On the departure of the Romans, a cloud of thick darkness falls upon the history of the country and its inhabitants. When, about a century and a half later, it begins to rise, Renfrewshire is discovered forming part of the British Kingdom of Cumbria or Strathclyde, one of the four Kingdoms which were then struggling for supremacy in the country. Of the other three, two were on the north of the Forth and Clyde—the Scottish in the west and the Pictish in the east. The third was the Kingdom of Bernicia, which occupied the south-east corner of the country and stretched from the Firth of Forth to the Tees. Strathclyde extended from the river Derwent in Cumberland to the Clyde and probably beyond it. On the west it included the counties of Dumfries and Ayr. On the east it stretched beyond Edinburgh, and was bounded in that direction and to the south-east by the Anglian Kingdom of Bernicia.

Of the history of Strathclyde during the hundred and fifty years referred to, little is known. According to Dr. Skene, the first of the twelve battles fought by King Arthur against the Saxons took place at the mouth of the Glein, which falls into the Irvine in the parish of Loudon, after which he invaded the regions about the wall in the Lennox occupied by the Saxons, and there met them in four pitched battles. If this was so, Arthur, unless he took a very round-about way, must have marched through Renfrewshire in order to reach the Lennox. There is but one place in the shire, however, which can claim even the remotest connection with this “ more or less historical and unmythical hero,” and that is, Arthurlie in the parish of Neilston.

At that time Renfrewshire appears to have been the seat of the family of Caw, commonly called Caw Cawlwydd or Caw Prvdyn, one of whose sons was Gildas the historian. In one of the lives of Gildas he is said to have been the son of Caunus, who reigned in Areclutha. Areclutha signifies a district lying along the Clyde, and as a description may suit the Lennox just as well as Renfrewshire. But two stories told in the life of S. Cadoc show that the district referred to is the County of Renfrew. While the saint was building a monastery near the mountain Bannawc, he found the grave of a giant, who rose and informed him that he was Caw of Prydyn, and that he had been a king and had reigned beyond the mountain Bannawc. The monastery, according to the second story, was built in regione Lintheami, or Cambuslang, the church of which is dedicated to S. Cadoc. Punning through the adjoining parish of Carmunnock, formerly Carmannock, and on the borders of Ayrshire is a range of hills, which terminates in Renfrewshire. This range of hills Dr. Skene has identified with the mountain Bannawe of the legend. Thus the life of the saint confirms the statement made in the life of the historian, and shows that during the century and a half which followed the departure of the Romans, the reigning family in the shire was that of Caw Prydyn. At the same period families of the race of Coel or Coil were reigning in Cunningham, Kyle, and Carrick.

After the battle of Arderydd (a.d. 573), ten years after S. Columba landed at Iona, and two years before he secured, at the Synod of Drumceatt, the independence of Dalriada, Rydderch Hael or Roderick the Liberal, King of Strathclyde, took the important step of removing his capital from Carlisle to Alcluith or Dumbarton, the fort of the Britons—a place which he would hardly have selected for it, had the fortress stood, as is usually supposed, on the most northerly limit of his kingdom. His father appears to have reigned before him, and after his father, one Morken, of whom we hear in Jocelin’s life of S. Kentigern, though it may be that he was only one of the lesser reguli whose territories Roderick absorbed into his own. Roderick was acquainted with S. Columba, who, on being asked, assured him that he would die not by the hands of his enemies, but in his own house—which prophecy, Adamnan tells us, was strictly fulfilled.

Renfrewshire lies under the shadow of the ancient capital of Strathclyde on the rock of Dumbarton, and, though for centuries its history, as far as our knowledge goes, is a perfect blank, there can be no doubt that during that period it passed through many vicissitudes and bore its share in the wars and privations and miseries which formed so large a part of the history of the ill-fated kingdom to which it belonged.

Of the three other kingdoms in the country, that from which the kingdom of Strathclyde had most to fear was the Anglian kingdom of Bernicia, more especially when united under oue crown to the kingdom of Deira.

From the Dalriadic Scots it had least to fear. Like the Britons the Scots were Celts. The Saxons and the Piets were their common enemies, and they were often united in arms against them.

In 594, Aethelfrith, grandson of Ida, became King of Bernicia and proved himself one of the most powerful rulers of the time. According to Bede no ruler before him did so much harm to the Britons by reducing them to his sway and planting Angles among them. In their conflicts with him the Britons were for obvious reasons supported by the Scots, but at the battle of Degsastan, in 603, he so thoroughly defeated the allies that until Bede’s day, more than a century after, it was said that no Scottish king dared to carry arms against the Angles. Edwin of Deira, who defeated and succeeded Aethelfrith, made his hand felt among the Britons still more heavily. He wrested Mynyd Agned from them and named it after himself, Edwinesburgh or Edinburgh, On his death in 633 the Britons regained their freedom, but they were soon reduced to subjection again by his son Oswald. They were free again in 642, and were then fighting against their natural allies, the Scots of Dalriada, whose King, Donald Brec, they defeated and slew at a battle fought in Strathcarron. In the same year they were fighting with Oswiu, King of Bernicia. But having got rid of his enemy Penda, in 685, at a battle fought near Leeds, Oswiu shortly afterwards made himself master of Strathclyde, Dalriada, and part of the Pictish kingdom, and for nearly thirty years exercised an effective control over almost the whole of Scotland. In 670 he was succeeded by Ecgfrith, who extended his rule as far west as Cunningham, and gave Carlisle to S. Cuthbert. With the defeat of Ecgfrith at Nectan’s Mere, in 685, Strathclyde once more regained its freedom. In 756 Eadberct of Northumbria and Angus Mac Fergus, King of the Piets, joined hands against the Britons, seized Dumbarton, and reduced Strathclyde to subjection. Its king at the time was Dungal, grandson of Beli. He is said to have reigned till the year 760 ; but from 758 to 789 the real master of Strathclyde, was Angus the Pictish king.

With the opening years of the ninth century came a new enemy. Already in 793 the Northmen had begun their work of havoc in northern Britain by attacking the Northumbrian kingdom. In 802 they burnt the buildings of Iona, and repeating their visit four years later slew sixty-eight persons, a number of whom were monks. About sixty-five years later, in the fourth year of Constantine II., son of Kenneth Mac Alpin, Olaf the White, the Norwegian King of Dublin, landed on the west coast of Scotland, and harried the country for two months and a half. Whether his raids reached as far east as Renfrewshire there is nothing to show, though it is not improbable that they did. Four years later he sailed up the Clyde, and, after a siege of four months, took Dumbarton. In 872 Artga, the King of Strathclyde, was slain, as the chronicle puts it, by the counsel of Constantine II. The last native prince of Strathclyde was Eocha, son of Run, by the daughter of Kenneth Mac Alpin. During his reign the kingdom was again overrun by the Northmen. He died somewhere between the years 900 and 918, and was succeeded by Donald, brother to Constantine III., King of Scots.

But a Scots dynasty upon the throne of Strathclyde did not mean the union of the kingdom to the Scottish Crown. The Britons fought along with the Scots and Danes against Athelstane at the famous battle of Brunanburh in 934. Later on their territory was overrun by the Danes. Edmund Ironsides drove them out in 945, and then handed the Cumbrian Kingdom over to Malcolm I. of Scotland on condition that he should be his “ fellow worker.” But in 971 the Britons once more asserted their independence, and at a battle fought in that year defeated and slew Cuilean the Scots King and his brother, thus proving “ that in spite of their misfortunes they were still formidable rivals to the Scots.” In 1018 the two kingdoms were again in league, and at the battle of Carham on the Tweed, Owen, the King of Strathclyde, contributed largely to Malcolm’s signal victory over the Northumbrians. Owen was the last independent King of Strathclyde. On his death Malcolm appointed his own grandson Duncan to succeed him, and Strathclyde was thenceforth an appanage of the Scottish Crown. It continued to be ruled by princes until 1224, when, on the accession of David, Prince of Cumbria, to the Scottish throne, it was finally united to the Scottish Crown, and Renfrewshire became an integral part of the kingdom of Scotland.