Lawrie's Early Scottish Charters gives some notes about a notitia we've been discussing on a different thread. Extracting just some of the relevant pieces, he says:
This notitia is in the Registr. Prior. St. And., fol. 5ib ; Bannatyne
Club edition, p. 115 ; Reeves' Culdees, p. 127.
It speaks of Ethelred as "vir venerandae memoriae," whence it
may be concluded that he was dead before the notice was written.
Robertson (Early Kings, I., p. 151) says that Ethelred survived his
parents only a very short time.
The grant was given at Abernethy, and confirmed by David and
Alexander, two of Ethelred's brothers, in presence of the Earl of Fife,
and of several priests of Abernethy....
Ethelred was the third son of King Malcolm III. and Queen
Margaret. He cannot have been older than fifteen or sixteen in
1093 when his father and mother died.
In his youth he received Admore from his parents, possibly as
part of the Earldom of Fife. It seems to me probable that he
became a monk, and that he remained in the retirement of the Abbey of Dunkeld during the stormy years when his uncle Donald was
king.
I do not agree with Skene and other writers who assume that
Ethelred was a ' lay ' abbot.
That opinion is founded partly on the fact that Ethelred was an
earl, and partly on the fact that a former abbot of Dunkeld, Crinan
(Ethelred's great-grandfather), was married, and fought and fell in
battle, but these circumstances are not incompatible with holy orders
in those early days.
Wyntoun, prior of St. Serf's, makes no mention of Ethelred in
his Chronicle. Fordun said (5. 24): "De Ethelred nihil certum
scriptis invenio ubi sit mortuus vel sepultus : praeter ut quidam
asserunt in antiqua ecclesia S. Andreae de Kilrimont humatus
requiescit." [Nothing is certain is known about Ethelred died or was buried.] ...
Insuper Comes de Fyf. "Insuper" may be a mistake for a word
meaning "formerly." G. E. C. suggests that Ethelred was Earl of
Forthrif, and Constantine Earl of Fife. It was an early tradition that
Macduff was Thane of Fife in the reign of Macbeth, and that in the
time of King Malcolm he became Earl. Mr. Skene thinks Macduff
is 'fictitious,' the creation of Fordun, and Robertson (Early Kings,
I., p. 124): "Fife was 'in the Crown' in the days of Malcolm Can-
more, who granted the Earldom to his son Ethelred. The Macduff, Earl of Fife, of the fabulists a being unknown to Wynton must be
put down as a myth." These eminent writers are mistaken. Macduff
may be a myth, but he is certainly not the creation of Fordun.
Wyntoun, who calls him Thane of Fife, gives a long account of him
which agrees with Fordun....
In Ethelred's time the monastery [Abernethy] had not yet been secularized ; less
than a century afterwards part of the endowments had passed into the
lands of Laurence, the son of Orm, who in one charter is called the
abbot. In 1272 Abernethy was made a priory canons regular
from Inchaffray displacing the Culdees.
p. ii. Constantinus, Comes de Fife, was probably the son, or
grandson, of Macduff of Fife, who lived in the reigns of Duncan I.,
Macbeth, and Malcolm III.
Constantine Macdufe is one of the witnesses to the doubtful charter
by Edgar to Durham (No. XV., ante, p. 12).
Constantine Comes is a witness (circa A.D. 1 128) to the great charter
by David I. to Dunfermline Abbey (No. LXXiv., ante, p. 61), with
Gillemichel Mac duf, whom I take to be his son and successor in the
Earldom.
Here he is described as " vir discretissimus," and in the record of
the suit between the brethren of St. Serf and Sir Robert Burgonensis
(circa A.D. 1128, No. LXXX., ante, p. 66) he was one of the judges ; he
was styled " magnus judex in Scotia" and " vir discretus et facundus."
He appeared at the trial "cum satrapy s et satellitibus ex exercitu de
Fyf." He is mentioned in Charter xciv., ante, p. 76, as having with-
held by force the shire of Kirkcaldy from the Abbey of Dunfermline.
https://archive.org/stream/earlyscottishcha00lawruoft#page/242/mode...