What part of the recovered provinces he formed into the new province of Valentia cannot be determined with certainty. It is usually assumed to have consisted of the territory between the walls; but this assertion, though now accepted as almost a self-evident proposition, dates no further back than the appearance of the spurious work attributed to Richard of Cirencester, and rests upon his authority alone. Horsley, who wrote before his date, considers that this part of Roman Britain belonged to the province of Maxima Cæsariensis, and is borne out by the distribution of the troops as given in the Notitia Imperii; the whole of those stationed from the Humber to the southern wall and along the line of the wall which evidently guarded the northern frontier, being placed under the same commander, the ‘Dux Britanniæ,’ That it was a part of the recovered provinces, and not new territory, is certain, and equally so that it was on the frontier; but it is more probable that the new province was designed to protect Roman Britain against the new invaders, who had appeared for the first time under the name of Scots, and who directed their attacks mainly on the west coast; and this is confirmed by the appearance in the Notitia of a new military commander called the ‘Comes Britanniarum,’ who had under him three bodies of infantry, one of which is called ‘Britanniciani juniores,’ and six bodies of cavalry, one being placed at a station on the north of the Don, and another transferred to the Saxon shore, which would place his command south of the Humber and Mersey. As the ‘Comes littoris Saxonici’ protected the south-eastern coast, and the ‘Dux Britanniæ’ the northern frontier, this new military functionary was probably created for the protection of the western frontier exposed to the Irish Channel. This position also corresponds with the order in which the provinces are enumerated in the Notitia.[95] In the absence of any trustworthy authority as to its position, and looking merely to the slender indications from which any inference may be drawn, we do not hesitate to pronounce that the true Valentia was that part of the province most exposed to the attacks of the Scots, and afterwards called Wales.