Scots Peerage, 1 (1904): 8 (sub Kings of Scotland) assigns two wives
to Robert I [de Brus], King of Scotland. This material can be found
at the following weblink:
http://books.google.com/books?id=_KEKAA ... ud#PPA8,M1
Regarding Robert de Brus' first wife, Isabel of Mar, it states the
following:
"He married, first, about 1295, Isabella, daughter of Donald, tenth
Earl of Mar, by whom he had an only child." END OF QUOTE.
No documention is provided for this marriage.
In a footnote, the editor explains that this wife "is called Matilda
in a warrant by Edward I. 13 October 1296, Cal. of Docs., ii. 850."
Thus, in spite of the fact that the editor was faced with evidence
that Robert de Brus had a wife named Maud in 1296, he still morphed
Maud into the first wife Isabel of Mar. In truth, Robert de Brus had
three wives, of whom Maud Fitz Alan was the second wife.
But how does Douglas Richardson know that the SP editor had not simply mistaken a record of Robert's father of the same name with this wife named Matilda in October 1296?
Charters listed in Ruth Blakely's book oon the Brus family, cited earlier, make it clear that the Robert who inherited Annandale and other lands from his father in 1295 was still using the title "earl of Carrick" along with "lord of Annandale", etc, _after_ this time, so the stronger likelihood must be that he, and not his son Robert who later became king of Scots, was the man who married Maud Fitzalan. From all we know, it appears that only the elder man (died 1304) would have been called both "earl of Carrick" and "lord of Annandale" in 1296. This can be shown from his own charters. Where is Douglas Richardson's evidence that the same can be shown for the younger Robert?
Without much firmer evidence than has been offered, there is no good reason to overturn SP's account of the two, not three, marriages of King Robert the Bruce.