Gilbert recognised as earl of Angus in English royal rolls between 19 April and 22 June 1267 (<em>CDS</em> I, nos. 2429, 2432, 2433). The earldom seems to have been held in custody by Simon de Montfort, earl of Leicester, after the death of Earl Gilbert de Umfraville I (<em>ca.</em> 1244). The earl of Angus died shortly before 13 Oct. 1307. Probable date by death of Duncan the judex.