It has been suggested that after Earl John's death in 1231, the successor to the earldom of Caithness was a minor, which Earl Gilchrist's son, Magnus, could not have been in 1231, and that this minor and ward was a son of Magnus, and bore the same name as his father.
The wardship seems at first sight to be proved in Robertson's _Early Kings_,[6] and the proof is to the following effect:--Malcolm of Angus attested a charter in Earl John's lifetime on 22nd April 1231, using his own title of "Angus" only. After John's death, Malcolm attested another charter on 7th October 1232 as "M. Comite de Anegus et Katania,"[7] using, in addition to his own title of Angus, as was customary, the title of a ward, who was heir to another earldom, in this case that of Caithness. But on 3rd July 1236, Malcolm Earl of Angus, who lived till 1237 if not longer, attested a third charter using his own title of "Angus" only, without the addition "and of Caithness." These facts can be explained by his ward's having attained his majority and entered upon his earldom of Caithness between 7th October 1232 and 3rd July 1236. They cannot be explained by saying that "M" was not Malcolm, but Magnus, and that "M" stands for Gilchrist's son Magnus, who had become Earl of Caithness. For there was no "M. Comes de Angus" at the time save Malcolm, and Malcolm was therefore for about four years Earl of Caithness as well as of Angus.
Robertson's explanation is that Malcolm was Earl of Caithness only as guardian of a ward entitled to that earldom. The question then arises, as Robertson puts it, "who was the heir?" and he answers it, "certainly not his[8] uncle Magnus, son of Gillebride,[9] but very probably the son of Magnus by Earl John's daughter; the supposed grant of the Earldom to this Magnus being probably grounded upon his real marriage with the heiress," and he adds "If, on the death of Earl John in 1231, his grandson was an orphan and a minor, his wardship would naturally have been granted to the next of kin, his cousin the Earl of Angus."
One further charter has to be dealt with. In _Reg. Hon. de Morton_, vol. I, p. xxxv, cited in _Origines Parochiales_ vol. II, p. 805, a grant by King Alexander II, to Patrick Earl of Dunbar dated 7th July 1235 is attested by a witness, whose name or initial is illegible, but who is styled ... _Earl_ ... _Katanay_, ... _Comite_ ... _Katanay_, and a confident opinion is expressed in a note to the citation that the witness was Magnus, Earl of Caithness. Now, Earl John's daughter was taken as a hostage on August 1, 1214, and, if she was then marriageable and was married at once, her eldest child could have been born about May 1215, and would attain twenty-one about May 1236, but to suppose her son of the name of Magnus to have been the ward for whom the Earldom of Caithness was being kept till 7th July 1235 from 1232 and that he had become Earl of Caithness on the 7th July 1235 seems impossible. If the blank should be filled up with "de Anegus et," then Malcolm Earl of Angus must still have been the guardian, and the ward's father and mother must both have been dead by 7th October 1232. This involves three unproved assumptions, of two unrecorded deaths and one unrecorded birth.