But, to return to Maud's charter, the point which I am anxious to emphasize is that of the formula she employs, namely, "do et concedo," as against the "sciatis me fecisse" of an original creation. I trace this distinction in later years, when her son, who had already, as we have seen, confirmed this charter to Aubrey, again confirmed it when king (1156), employing for that purpose the same formula: "Sciatis me dedisse et concessisse comiti Alberico." Conversely, in the case of Hugh Bigod, he employs the formula: "Sciatis me fecisse Hugonem Bigot comitem de Norfolca" (1155), this being an earldom of Stephen's creation, and, so far as we know, of his alone. This is a view which should be accepted with caution, but which has, if correct, an important bearing. The very remarkable shifting clause as to the county of which the grantee should be earl requires separate notice. The axiom from which I start is this: When a feudatory was created an earl, he took if he could for his "comitatus" the county in which was situated the chief seat of his power, his "Caput Baroniæ." If this county had an earl already he then took the nearest county that remained available. Thus Norfolk fell to Bigod, Essex to Mandeville, Sussex to Albini, Derby to Ferrers, and so on. De Clare, the seat of whose power was in Suffolk, though closely adjoining Essex, took Herts, probably for the reason that Mandeville had already obtained Essex, while Bigod's province, being in truth the old earldom of the East Angles—"Comes de Estangle," as Henry of Huntingdon terms him,—took in Suffolk. So now, Aubrey de Vere probably selected Cambridgeshire as the nearest available county to his stronghold at Castle Hedingham.[592] But the Empress, we see, promised it only on the strange condition that her uncle was not already in possession. I say "the strange condition," for one would surely have thought that she knew whether he was or not. Moreover, the dignity was then held not by her uncle, but by his son, and is described as the earldom of Huntingdon, never as the earldom of Cambridge. The first of these difficulties is explained by the fact that the King of Scots had, early in the reign, made over the earldom to his son Henry, to avoid becoming himself the "man" of the King of England. The second requires special notice.