Óengus I Óengus son of Fergus ( ; Old Irish : " Óengus mac Fergusso " , " Angus mac Fergus " ) , was king of the Picts from 732 until his death in 761 . His reign can be reconstructed in some detail from a variety of sources . Óengus became the chief king in Pictland following a period of civil war in the late 720s . During his reign , the neighbouring kingdom of Dál Riata was subjugated and the kingdom of Strathclyde was attacked with less success . The most powerful ruler in Scotland for over two decades , he was involved in wars in Ireland and England . Kings from Óengus ' s family dominated Pictland until 839 when a disastrous defeat at the hands of Vikings began a new period of instability , which ended with the coming to power of Cináed mac Ailpín . Sources and background . Surviving Pictish sources for the period are few , limited to king lists , the original of which was prepared in the early 720s , and a number of accounts relating to the foundation of St Andrews , then called Cennrígmonaid . Beyond Pictland , the principal sources are the Irish annals , of which the " Annals of Ulster " and the " Annals of Tigernach " are the most reliable . These include materials from an annal kept at the monastery of Iona in Scotland . Óengus and the Picts appear occasionally in Welsh sources , such as the " Annales Cambriae " , and more frequently in Northumbria n sources , of which the Continuation of Bede ' s chronicle and the " Historia Regum Anglorum " attributed to Symeon of Durham are the most important . The Picts were one of four political groups in north Britain in the early 8th century . Pictland ran from the River Forth northwards , including Orkney , Shetland and the Western Isles . Prior to the Viking Age , the main power in Pictland appears to have been the kingdom of Fortriu . Known high - status sites in Fortriu include Burghead and Craig Phádraig by Inverness . Pictland appears to have had only one bishop with his seat at Rosemarkie . From the Forth south to the River Humber lay the kingdom of Northumbria . Once the dominant force in Britain , it remained a powerful kingdom , but the end of the old dynasty of kings with the death of Osric in 729 led to conflict between rival families for the throne . The growing power of the Mercian kingdom to the south added to the problems faced by Northumbrian kings . For most of Óengus ' s reign Northumbria was ruled by the capable King Eadberht Eating . To the south - west of Pictland were the Gaels of Dál Riata where the kingship was disputed between the Cenél Loairn of northern Argyll and the Cenél nGabráin of Kintyre . In 723 Selbach mac Ferchair abdicated as head of the Cenél Loairn and king of Dál Riata in favour of his son Dúngal , who was driven out as king of Dál Riata by Eochaid mac Echdach of the Cenél nGabráin in 726 . Dúngal and Eochaid were still in conflict as late as 731 , when Dúngal burnt Tarbert . The history of the fourth group , the Britons of Alt Clut , later the kingdom of Strathclyde , leaves little trace in the record . King Teudebur map Beli had ruled from Dumbarton Rock since 722 , and continued to do so until his death in 752 when his son Dumnagual succeeded him . Rise to power . Irish genealogies make Óengus a member of the Eóganachta of Munster , as a descendant of Coirpre Cruthnechán or " Cairbre the little Pict " , a mythological emanation or double of Coirpre Luachra mac Cuirc , legendary son of Conall Corc , and ancestor of the Eóganacht Locha Léin , rulers of the kingdom of Iarmuman . The branch of the kindred from which he came , known in the annals as the Eoghanachta Magh Geirginn , were said located in an area known as Circinn , usually associated with modern Angus and the Mearns . His early life is unknown ; Óengus was middle - aged by the time he entered into history . His close kin included at least two sons , Bridei ( died 736 ) and Talorgan ( died 782 ) , and two brothers , Talorgan ( died 750 ) and Bridei ( died 763 ) . King Nechtan son of Der - Ile abdicated to enter a monastery in 724 and was imprisoned by his successor Drest in 726 . In 728 and 729 , four kings competed for power in Pictland : Drest ; Nechtan ; Alpín , of whom little is known ; and lastly Óengus , who was a partisan of Nechtan , and perhaps his acknowledged heir . Four battles large enough to be recorded in Ireland were fought in 728 and 729 . Alpín was defeated twice by Óengus , after which Nechtan was restored to power . In 729 a battle between supporters of Óengus and Nechtan ' s enemies was fought at Monith Carno ( traditionally Cairn o ' Mount , near Fettercairn ) where the supporters of Óengus were victorious . Nechtan was restored to the kingship , probably until his death in 732 . On 12 August 729 Óengus defeated and killed Drest in battle at Druimm Derg Blathuug , a place which has not been identified . Piercing of Dal Riata . In the 730s , Óengus fought against Dál Riata whose traditional overlords and protectors in Ireland , the Cenél Conaill , were much weakened at this time . A fleet from Dál Riata fought for Flaithbertach mac Loingsig , chief of the Cenél Conaill , in his war with Áed Allán of the Cenél nEógan , and suffered heavy losses in 733 . Dál Riata was ruled by Eochaid mac Echdach of the Cenél nGabráin who died in 733 , and the king lists are unclear as to who , if anyone , succeeded him as overking . The Cenél Loairn of north Argyll were ruled by Dúngal mac Selbaig whom Eochaid had deposed as overking of Dál Riata in the 720s . Fighting between the Picts , led by Óengus ' s son Bridei , and the Dál Riata , led by Talorgan mac Congussa , is recorded in 731 . In 733 , Dúngal mac Selbaig " profaned [ the sanctuary ] of Tory Island when he dragged Bridei out of it . " Dúngal , previously deposed as overking of Dál Riata , was overthrown as king of the Cenél Loairn and replaced by his first cousin Muiredach mac Ainbcellaig . In 734 Talorgan mac Congussa was handed over to the Picts by his brother and drowned by them . Talorgan son of Drostan was captured near Dún Ollaigh . He appears to have been the King of Atholl , and was drowned on Óengus ' s order in 739 . Dúngal too was a target in this year . He was wounded , the unidentified fortress of Dún Leithfinn was destroyed , and he " fled into Ireland , to be out of the power of Óengus . " The annals report a second campaign by Óengus against the Dál Riata in 736 . Dúngal , who had returned from Ireland , and his brother Feradach , were captured and bound in chains . The fortresses of Creic and Dunadd were taken . Muiredach of the Cenél Loairn was no more successful , defeated with heavy loss by Óengus ' s brother Talorgan mac Fergusa , perhaps by Loch Awe . A final campaign in 741 saw the Dál Riata again defeated . This was recorded in the " Annals of Ulster " as " Percutio Dál Riatai la h - Óengus m . Forggusso " , the " smiting of Dál Riata by Óengus son of Fergus " . With this Dál Riata disappears from the record for a generation . It may be that Óengus was involved in wars in Ireland , perhaps fighting with Áed Allán , or against him as an ally of Cathal mac Finguine . The evidence for such involvement is limited . There is the presence of Óengus ' s son Bridei at Tory Island , on the north - west coast of Donegal in 733 , close to the lands of Áed Allán ' s enemy Flaithbertach mac Loingsig . Less certainly , the " Fragmentary Annals of Ireland " report the presence of a Pictish fleet from Fortriu fighting for Flaithbertach in 733 rather than against him . Alt Clut , Northumbria , and Mercia . In 740 , a war between the Picts and the Northumbrians is reported , during which Æthelbald , King of Mercia , took advantage of the absence of Eadberht of Northumbria to ravage his lands , and perhaps burn York . The reason for the war is unclear , but it has been suggested that it was related to the killing of Earnwine son of Eadwulf on Eadberht ' s orders . Earnwine ' s father had been an exile in the north after his defeat in the civil war of 705 – 706 , and it may be that Óengus , or Æthelbald , or both , had tried to place him on the Northumbrian throne . Battles between the Picts and the Britons of Alt Clut , or Strathclyde , are recorded in 744 and again in 750 , when Kyle was taken from Alt Clut by Eadberht of Northumbria . The 750 battle between the Britons and the Picts is reported at a place named Mocetauc ( perhaps Mugdock near Milngavie ) in which Talorgan mac Fergusa , Óengus ' s brother , was killed . Following the defeat in 750 , the " Annals of Ulster " record " the ebbing of the sovereignty of Óengus " . This is thought to refer to the coming to power of Áed Find , son of Eochaid mac Echdach , in all or part of Dál Riata , and his rejection of Óengus ' s overlordship . Unlike the straightforward narrative of the attacks on Dál Riata , a number of interpretations have been offered of the relations between Óengus , Eadberht and Æthelbald in the period from 740 to 750 . One suggestion is that Óengus and Æthelbald were allied against Eadberht , or even that they exercised a joint rulership of Britain , or bretwalda ship , Óengus collecting tribute north of the River Humber and Æthelbald south of the Humber . This rests largely on a confused passage in Symeon of Durham ' s " Historia Regum Anglorum " , and it has more recently been suggested that the interpretation offered by Frank Stenton — that it is based on a textual error and that Óengus and Æthelbald were not associated in any sort of joint overlordship — is the correct one . In 756 , Óengus is found campaigning alongside Eadberht of Northumbria . The campaign is reported as follows : In the year of the Lord ' s incarnation 756 , king Eadberht in the eighteenth year of his reign , and Unust , king of Picts led armies to the town of Dumbarton . And hence the Britons accepted terms there , on the first day of the month of August . But on the tenth day of the same month perished almost the whole army which he led from Ouania to Niwanbirig . That Ouania is Govan is now reasonably certain , but the location of Newanbirig is less so . Although there are very many Newburghs , it is Newburgh - on - Tyne near Hexham that has been the preferred location . An alternative interpretation of the events of 756 has been advanced : it identifies Newanbirig with Newborough by Lichfield in the kingdom of Mercia . A defeat here for Eadberht and Óengus by Æthelbald ' s Mercians would correspond with the claim in the Saint Andrews foundation legends that a king named Óengus son of Fergus founded the church there as a thanksgiving to Saint Andrew for saving him after a defeat in Mercia . The cult of Saint Andrew . The story of the foundation of St Andrews , originally " Cennrígmonaid " , is not contemporary and may contain many inventions . The Irish annals report the death of " Tuathalán , abbot of Cinrigh Móna " , in 747 , making it certain that St Andrews had been founded before that date , probably by Óengus or by Nechtan son of Der - Ilei . It is generally presumed that the St Andrews Sarcophagus was executed at the command of Óengus . Later generations may have conflated this king Óengus with the 9th century king of the same name . The choice of David as a model is , as Alex Woolf notes , an appropriate one : David too was an usurper . The cult of Saint Andrew may have come to Pictland from Northumbria , as had the cult of Saint Peter which had been favoured by Nechtan , and in particular from the monastery at Hexham which was dedicated to Saint Andrew . This apparent connection with the Northumbrian church may have left a written record . Óengus , like his successors and possible kinsmen Caustantín and Eógan , is recorded prominently in the " Liber Vitae Ecclesiae Dunelmensis " , a list of some 3000 benefactors for whom prayers were said in religious institutions connected with Durham . Death and legacy . Óengus died in 761 , " aged probably more than seventy , . . . the dominating figure in the politics of Northern Britain " . His death is reported in the usual brief style by the annalists , except for the continuator of Bede in Northumbria , possibly relying upon a Dál Riata source , who wrote : Óengus , king of the Picts , died . From the beginning of his reign right to the end he perpetrated bloody crimes , like a tyrannical slaughterer . The Pictish Chronicle king lists have it that he was succeeded by his brother Bridei . His son Talorgan was later king , and is the first son of a Pictish king known to have become king . The following 9th - century Irish praise poem from the Book of Leinster is associated with Óengus : Good the day when Óengus took Alba , hilly Alba with its strong chiefs ; he brought battle to palisaded towns , with feet , with hands , with broad shields . An assessment of Óengus is problematic , not least because annalistic sources provide very little information on Scotland in the succeeding generations . His apparent Irish links add to the long list of arguments which challenge the idea that the " Gaelicisation " of eastern Scotland began in the time of Cináed mac Ailpín ; indeed there are good reasons for believing that process began before Óengus ' s reign . Many of the Pictish kings until the death of Eógan mac Óengusa in 839 belong to the family of Óengus , in particular the 9th century sons of Fergus , Caustantín and Óengus . The amount of information which has survived about Óengus compared with other Pictish kings , the nature and geographical range of his activities and the length of his reign combine to make King Óengus one of the most significant rulers of the insular Dark Ages .