Two races seem to have entered, as original elements, into the population of Ireland and of the Highlands of Scotland. These were the race of the Scots and the people termed by the early Irish authorities the race of the Cruithne. The latter appear everywhere to have preceded the former.
Prior to the sixth century, the Cruithne alone seem to have formed the population of the Scotch Highlands. In Ireland they formed the original population of Ulster and the north part of Leinster. Connaught, the rest of Leinster, and Munster, were Scottish. The east and north of Ireland appear to have been most exposed to external influences, and to have suffered the greatest changes in their population. In the south and west it was more permanent; and from Connaught and Leinster the royal races of the Scots emerged, while their colonies proceeded from south and west to north and east.
The traditionary history of Ireland records an early settlement of the Scots among the Cruithne of Ulster, termed from its mythic founder Dalriada, and likewise the fall of the great seat of the Cruithnian kingdom, called Emania, before an expedition, led by a scion of the Scottish royal race, who established the kingdom of Orgialla on its ruins. It is certain that, while we have reason to believe that the Cruithne formed the original population of the whole of Ulster, we find them in the historic period confined to certain districts in Ulster only, although their kings retained the title of kings of Ulster.
In the beginning of the sixth century, the Scots, who are frequently recorded by the Roman writers as forming part of the predatory bands who, from time to time, assailed the Roman province, and finally overthrew their empire in Britain, passed over to the opposite coast of Argyll, and effected a permanent settlement there, which, from its mother tribe, was also called Dalriada. This settlement is recorded, by the oldest authority, to have taken place twenty years after the battle of Ocha, which was fought in the year 483, and, therefore, in the year 503. The territory occupied by this settlement of the Scots was the south part of Argyllshire, consisting of the districts of Cowall, Kintyre, Knapdale, Argyll-proper, Lorn, and probably part of Morvern, with the islands of Isla, Iona, Arran, and the small islands adjacent. The boundary which separated them from the Cruithne was on the east, the range of mountains termed Drumalban, a mountain chain which still separates the county of Argyll from that of Perth. On the north, the boundary, which probably was not very distinct, and varied from time to time, seems to have been coincident with a line extending from the Island of Colonsay through the Island of Mull to the centre of the district of Morvern, through which it passed to the shores of the Luine Loch opposite Appin.[20] The rest of the Highlands was still occupied by the Cruithne, who were Pagans, while the Dalriadic Scots were Christians.
In the year 563, an event took place which was destined to exercise a powerful influence both on the condition and the language of the population. This was the mission of Saint Columba, a Scot from Ireland, to convert the Cruithne to the Christian faith, and the consequent foundation of the Monastery of Iona, which became the seat of learning, and the source of all ecclesiastical authority, both for the Cruithne and the Dalriadic Scots, from whence innumerable Scottish clergy issued, who spread over the country and founded churches among the Cruithne under its influence and authority.
The platform occupied by the two populations, embracing both Ireland and the Highlands of Scotland, in the sixth century, thus showed in the south and west of Ireland pure Scots; in the north and east settlements of Scots among the Cruithne, gradually confining the latter to isolated districts; in Argyll, a Scottish settlement among the Cruithne of Alban; and in the rest of the Highlands pure Cruithne; but over both Scots and Cruithne in Alban a Scottish clergy, who brought a cultivated and literary language with them.
In Ireland the Gaelic spoken in the different provinces varies, and probably has always varied from each other. They differ in words, pronunciation, and idiom; and in grammatical construction and idiom there is a marked difference between the Gaelic of the northern and of the southern half of Ireland. The written language resembles most the language of the south and west of Ireland. It seems to have been formed from it, and to have become the common language of the literary and cultivated class, while the other dialects remained as the spoken language of their respective populations.
This written language was brought over to Scotland in the sixth century by Columba and his clergy, who introduced it, with Christianity, among the Cruithne; where, however, the native dialect must have received some cultivation, as we find that he was opposed by Magi, which implies a literary class among the Pagan Cruithne. At this time there was so little political separation between the two countries, that the Scots of British Dalriada remained subject to the Irish Dalriada, from which they emerged, till the year 573, when Aedan, son of Gabran, became king of Scotch Dalriada, and, at the great Council of Drumceat, it was declared independent of Irish Dalriada, and he was crowned as its first independent monarch. The Cruithne of Ireland, likewise, formed part of that great Cruithnian kingdom, which had its head-quarters in Scotland, till the reign of Fiacha mac Baedan, King of Ulster, who ruled over the Irish Cruithne from 589 to 626, and probably in the year 608, when they threw off the yoke of the Cruithne of Scotland.[21]
The Cruithne and the Scots of Ireland and of Scotland then first became separated from, and independent of, each other, and a complete political separation took place between the two countries.
The Cruithne of Scotland remained under the influence of the Scottish clergy till the beginning of the eighth century, when their king, Nectan, adopted the usages of the Romish party, and in 717 expelled the Scottish clergy out of his dominions across the boundary of Drumalban,[22] which separated them from the Scots of Dalriada, and a new clergy was introduced into that part of the country, occupied by the Cruithne, from the Anglic kingdom of Northumberland. In 731, we learn from Bede, who then closes his history, that the Scots of Dalriada were still confined within the same limits; and that no change had up to that date taken place in the relative positions of the two populations, the Cruithne and the Scots. After this date we know little of the history of the population of the Highlands till the middle of the ninth century, when we find that a great change had, in the interval, taken place in their political condition. The two populations had now become united in one kingdom, and a family of undoubted Scottish race ruled over the united people.