There is one still existing memorial by which the name of Offa yet survives in the mouths of men. This is Offa’s Dyke (called by the Welsh _Clawdd Offa_), a great earthen rampart flanked by a ditch, which ran from the mouth of the Dee to the mouth of the Wye, a distance of some 130 miles, and divided the territories of the Mercians from those of the Welsh. For a considerable portion of its course this rampart is still visible, in some places only as a low bank but in others showing a height of 30 feet to the summit of the mound from the bottom of the ditch on its western side. It nearly corresponds with the present boundary between England and Wales, except that it cuts off from England a portion of Hereford and the whole of Monmouth. In part of its course it is duplicated by another embankment called Wat’s Dyke, about three miles to the east of it, and this work also, in the belief of some antiquaries, belongs to the age of Offa. Though we are distinctly told, on good authority, that the object of this huge work was military defence, it is probable that, like the _Vallum_ in Northumberland and the _Pfahlgraben_ in Germany, it was also a geographical boundary, and served a useful purpose in time of peace, as marking the limit of two rival jurisdictions and clearly indicating to which of them pertained the duty of punishing robbery or murder committed on either side of the border. This dyke probably commemorates the result of the “Devastation of the southern Britons wrought by Offa” which is noted by the _Cambrian Annals_ under the years 778 and 784; and the effect of these campaigns seems to have been to push back the Welsh frontier from the Severn to the Wye--no unimportant augmentation of the Mercian kingdom. The diplomatic correspondence of the period shows us how large loomed the figure of Offa in the eyes of his contemporaries. Pope Hadrian I. in writing to Charlemagne calls him absolutely “rex Anglorum,” and at the same time earnestly expresses his disbelief in a rumour which had reached his ears that the two kings of the Franks and the Angles were plotting his own deposition from the papacy, and the appointment of a Frankish ecclesiastic in his place. This, however, was probably an idle rumour, set afloat by some of Hadrian’s enemies in order to work upon the fears of the elderly pontiff. Offa, himself, seems to have received the legates of the Holy See with reverence and to have availed himself of their help in regulating the affairs of his new archbishopric. Moreover, he ordained, probably as a thank-offering for the papal assistance in this matter, that his kingdom should send a yearly offering of 365 _mancuses_ (about £130), one for each day in the year, to the holy see.