In the 7th century, Dál Riata was the first territory in what is now the UK to conduct a census.

By the 9th century, the Gaels of Dál Riata ( Dalriada ) were subject to the kings of Fortriu of the family of Constantín mac Fergusa ( Constantine son of Fergus ).

The dominance of Fortriu came to an end in 839 with a defeat by Viking armies reported by the Annals of Ulster in which King Uen of Fortriu and his brother Bran, Constantín's nephews, together with the king of Dál Riata, Áed mac Boanta, " and others almost innumerable " were killed.

The situation of the Gaelic kingdoms of Dál Riata in western Scotland is uncertain.

The Frankish Annales Bertiniani may record the conquest of the Inner Hebrides, the seaward part of Dál Riata, by Northmen in 849.

These raiders would later found the Kingdom of Dál Riata in the West.

In the west were the Gaelic ( Goidelic )- speaking people of Dál Riata with their royal fortress at Dunadd in Argyll, with close links with the island of Ireland, from which they brought with them the name Scots.

There was also a merger of the Gaelic and Pictish crowns, although historians debate whether it was a Pictish takeover of Dál Riata, or the other way around.

The first written records of native life begin in the 6th century AD when the founding of the kingdom of Dál Riata took place.

The figure of Columba looms large in any history of Dál Riata and his founding of a monastery on Iona ensured that the kingdom would be of great importance in the spread of Christianity in northern Britain.

North of Dál Riata, the Inner and Outer Hebrides were nominally under Pictish control although the historical record is sparse.

The Scottish Gaelic language arrived via Ireland due to the growing influence of the kingdom of Dál Riata from the 6th century onwards and became the dominant language of the southern Hebrides at that time.

The larger islands have been continuously inhabited since Neolithic times, were influenced by the emergence of the kingdom of Dál Riata from 500 AD and then absorbed into the emerging Kingdom of Alba under Kenneth MacAlpin.

Map of Dál Riata at its height, c. 580 – 600.

During the 2nd century AD Irish influence was at work in the region and by the 6th century the kingdom of Dál Riata was established.

Dál Riata flourished from the time of Fergus Mór in the late fifth century until the Viking incursions that commenced in the late eighth century.

Rather than a conquest of the Picts, instead the idea of Pictish matrilineal succession, mentioned by Bede and apparently the only way to make sense of the list of Kings of the Picts found in the Pictish Chronicle, advanced the idea that Kenneth was a Gael, and a king of Dál Riata, who had inherited the throne of Pictland through a Pictish mother.

Kenneth's origins are uncertain, as are his ties, if any, to previous kings of the Picts or Dál Riata.

Medieval genealogies are unreliable sources, but many historians still accept Kenneth's descent from the established Cenél nGabráin, or at the very least from some unknown minor sept of the Dál Riata.

Pictland, also known as Pictavia, gradually merged with the Gaelic kingdom of Dál Riata to form the Kingdom of Alba ( Scotland ).

The Gaels of Dál Riata controlled their own region for a time, but suffered a series of defeats in the first third of the 7th century.

In the reign of Óengus mac Fergusa ( 729 – 761 ), Dál Riata was very much subject to the Pictish king.

Although it had its own kings from the 760s, it appears that Dál Riata did not recover.

A later Pictish king, Caustantín mac Fergusa ( 793 – 820 ), placed his son Domnall on the throne of Dál Riata ( 811 – 835 ).

The kingdom of Dál Riata was destroyed, certainly by the middle of the 9th century, when Ketil Flatnose is said to have founded the Kingdom of the Isles.

Suibhne, king of Dál nAraidi, was cursed by St Ronan and became a kind of half man, half bird, condemned to live out his life in the woods, fleeing from his human companions.

Oswald thus spent the remainder of his youth in the Scottish kingdom of Dál Riata in northern Britain, where he was converted to Christianity.

Shortly after becoming king, he asked the Irish of Dál Riata to send a bishop to facilitate the conversion of his people, and they sent Aidan for this purpose ; initially, the Irish sent an " austere " bishop who was unsuccessful in his mission, and Aidan, who proposed a gentler approach, was subsequently sent instead.

The kingdom of Dál Riata was located on the western coast of Scotland, and Viking incursions destroyed it after the death of its previous king, Áed mac Boanta in 839, according to the Annals of Ulster.

Dál Riata ( also Dalriada or Dalriata ) was a Gaelic overkingdom on the western coast of Scotland ( then Pict-land ) and parts of the Kingdom of Ulster.

Some scholars have seen no revival of Dál Riata after the long period of foreign domination ( after 637 to around 750 or 760 ), while others have seen a revival of Dál Riata under Áed Find ( 736-778 ), and later Kenneth MacAlpin ( Cináed mac Ailpín, who is claimed in some sources to have taken the kingship there in c. 840 following the disastrous defeat of the Pictish army by the Danes ): some even claim that the kingship of Fortriu was usurped by the Dál Riata several generations before MacAlpin ( 800-858 ).

If Iona was the greatest religious centre in Dál Riata, it was far from unique.

Bede offers a different, and probably older, account wherein Dál Riata was settled by a certain Reuda, which is more internally consistent, given that Old Irish Dál means portion or share, and is usually followed by the name of an eponymous founder.

However Dál Riata came to form, the period in which it arose was one of great instability in Ulster, following the loss of territory by the kingdom of Ulaid, including the ancient centre of Emain Macha, to the Airgíalla and the Uí Néill.

What is not in doubt is that Irish Dál Riata was a lesser kingdom of Ulaid.

The Kingship of Ulster was dominated by the Dál Fiatach and contested by the Cruithne kings of the Dál nAraidi.

The obvious conclusion is that whoever ruled the petty kingdoms of Dál Riata after its defeat and conquest in the 730s, only Áed Find and his brother Fergus drew the least attention of the chroniclers in Iona and Ireland.

It is unlikely that Dál Riata was ruled directly by Pictish kings, but it is argued that Domnall, son of Caustantín mac Fergusa, was king of Dál Riata from 811 to 835.

County Down was the ancient centre of the Dál Fiatach lands, and the chief royal site and religious centre of the Dál Fiatach was at Downpatrick from where they ruled Ulster for centuries.

The inclusion of Pictish kings from Caustantín to Eogán in the Duan led to the supposition that Dál Riata was ruled by Pictish kings, or rather that Dál Riata kings ruled Pictland, leading to supposition that the origins of the Kingdom of Alba lay in a Gaelic conquest of Pictland.

The independent existence of the kingdom of the Cenél Loairn, and that of Dál Riata, probably ended in 736, after which time it formed part of the kingdom of the Picts, ruled by Óengus mac Fergusa.

He ruled as king of the Cenél Loairn from around 698 until his abdication in 723, but it may be that he was undisputed ruler of Dál Riata only in the final years of his reign.

According to the Senchus, Dál Riata was divided into three sub-kingdoms in the 7th century, each ruled by a kin group named for their eponymous founder.

In Ireland, Dál Riata formed part of Ulster, ruled by Báetán mac Cairill of the Dál Fiatach.

Woolf has suggested that the name Airer Goídel replaced the name Dál Riata when the 9th-century Norse conquest split Irish Dál Riata and the islands of Alban Dál Riata off from mainland Alban Dál Riata ; the mainland area, renamed Airer Goídel, would have contrasted with the offshore islands of Innse Gall, literally " islands of the foreigners ", so-called because during the 9th to 12th centuries they were ruled by Norse-speaking Gall-Gaels.

Though he was the eldest son of Áedán mac Gabráin, Artúr mac Áedáin never became king of Dál Riata ; his brother Eochaid Buide ruled after his father's death.

It is likely that the association with the Uí Cheinnselaig is a later addition as other sources say that the king of Leinster who ruled from Naas in Patrick's time belonged to the later obscure kindred of Uí Garrchon, part of the Dál Messin Corb.

The Cenél Loairn of north Argyll were ruled by Dúngal mac Selbaig whom Eochaid had deposed as overking of Dál Riata in the 720s.