The following much cited description of Duncan, apparently from Burke's Peerage, has him:
"Command[ing] the Scottish left wing at the battle of Luncarty (c990) where the Danes were so crushingly defeated that their raids on that part of what subsequently became Perthshire, hitherto periodic and devastating, were terminated;
had (Crinan), with two younger sons ((1) Grim, Thane (hereditary tenant of the Crown) of Strathearn (west of Perth) and Baille (functionary with judicial powers) of Dule, killed 1010 at Battle of Mortlach, where Malcolm II King of Scots defeated invading Norsemen; (2) Duncan, ancestor of the Irving's of Dumfries and Forbes Irvine's of Drum)."
[Burke's Peerage & Baronetage, 106th Edition, Charles Mosley Editor-in-Chief, 1999]
This date is contradicted by the The Annals of Ulster record that "Donnchad the abbot of Dún Caillen" was killed in 965 in "a battle between the men of Scotland themselves"] http://fmg.ac/Projects/MedLands/SCOTTISH%20NOBILITY.htm#_Toc268450047
Also, it appears that the Battle of Luncarty is now considered an invention by Boece: http://canmore.rcahms.gov.uk/en/site/26719/details/luncarty/
Also, his parentage of Crinan is debated
"Since the abbacy of Dunkeld may have been hereditary in Crínán's family (his grandson Æthelred held the title), it has sometimes been suggested that Crínán was possibly the son of this earlier abbot of Dunkeld whose death is known from both the Irish and Scottish sources [e.g., AU; ESSH 1: 471, 473, 577; KKES 252]. While the relationship is not impossible, the chronology is very long (if true, Crinán would be eighty at his death in battle even if born in the year of his father's death), and there is no known evidence to support it. The alleged relationship cannot be accepted without further evidence.http://sbaldw.home.mindspring.com/hproject/prov/crina000.htm
Does anyone have anything new to add to this?
adds in an extra Duncan between this one & Crinan (potentially only to solve the problem of the chronological length of time between the purported father and son; but perhaps also because they want to accommodate the Duncan supposed to have died at the Battle of Luncarty):
Duncan, Mormaer of Atholl1
Duncan, Mormaer of Atholl was the son of Duncan (?).2
He was Lay Abbot of Dunkeld.2 He was also known as Duncan O'Neill.3 He gained the title of Mormaer of Atholl.1 He fought in the Battle of Luncarty circa 990, where he commanded the left wing, and where the Danes were so crushingly defeated that their raids on that part of what subsequently became Perthshire, ceased.2
Children of Duncan, Mormaer of Atholl
Grim, Thane of Strathearn2 d. 1010
Crinan, Mormaer of Atholl+1 b. c 975, d. c 1045
[S11] Alison Weir, Britain's Royal Family: A Complete Genealogy (London, U.K.: The Bodley Head, 1999), page 177. Hereinafter cited as Britain's Royal Family.
[S60] Charles and Hugh Brogan Mosley, editor, American Presidential Families (London, U.K.: Alan Sutton and Morris Genealogical Books, 1994), page 45. Hereinafter cited as American Presidential Families.
[S37] Charles Mosley, editor, Burke's Peerage, Baronetage & Knightage, 107th edition, 3 volumes (Wilmington, Delaware, U.S.A.: Burke's Peerage (Genealogical Books) Ltd, 2003), volume 1, page 1206. Hereinafter cited as Burke's Peerage and Baronetage, 107th edition.
There also seems to me to be a possibility of two people instead of one: an Abbot Duncan & a Mormaer Duncan:
"According to the Scottish Chronicle contained in the Poppleton Manuscript, Duncan ("Duchad"), abbot of Dunkeld, was killed, along with Dubdon, mormaer (?) (satrapas) of Atholl, in a battle between Dub mac Máel Coluim ("Niger") and Culén mac Illuilb ("Caniculus"), upon the ridge of Crup, in which Dub (king of Scotland) had the victory (over Culén, later king of Scotland) ["[Bellum] inter nigerum [et] Caniculum super dorsum Crup in quo Niger habuit uictoriam ubi cecidit Duchad abbas Duncalden et Dubdon satrapas Athochlach." Poppleton MS., KKES 252]. The Annals of Ulster place this battle in 965"
Which doesn't really solve anything here - because they both die in the battle - which, if it was in 965, still leaves us with the difficulty of either being Crinan's father.
So I'm just pointing out the possibility that this profile could still be two men. (Although I think we know pretty definitely? that by the time Crinan is Lay Abboy of Dunkeld, he is also the Mormaer of Atholl.)
http://www.geni.com/discussions/124169 where we decide it still makes most sense to keep the extra Duncan in - because there is a profile for him (presently designated as his brother - but with the info that should go with being the profile for his father).
The possibility of two people instead of one: an Abbot Duncan & a Mormaer Duncan remains up in the air