In 539 Witiges and Belisarius were locked in such deadly conflict that the Franks thought it a good opportunity to endeavour to invade Italy on their own behalf. Theudebert came over the Alps in person, with an army of 100,000 men, all footmen armed with lance and axe, save 300 nobles who rode around the king with shield and spear. First falling on his friends the Goths, then attacking the East-Romans in turn, Theudebert drove across the north of Italy, sacking Genoa, and wasting all the valley of the Po as far as Venetia. All the open country was in his hands, and the Goths and Romans had to shut themselves up in their fortresses. But a disease brought on by foul living fell upon the Franks, and so thinned their ranks that Theudebert had to retire homeward, relinquishing all he had gained save the possession of the passes of the Cottian Alps. It was, however, with his Italian plunder that he struck the first gold money which any barbarian king coined in his own name. Instead of placing the head of the emperor on his solidi, as had hitherto been the practice of Goth, Frank, and Burgundian, he represented his own image with shield and buckler, and the inscription _Dominus Noster Theudebertus Victor_, without any reference to Justinian as emperor or over-lord. Some of the pieces make him assume the more startling title of _Dominus Theudebertus Augustus_, as if he had aimed at uniting Gaul and Italy, and taking the style of Western Emperor; and, strange as this design may appear, it receives some countenance from a chronicler who declares that, after his Italian conquests, Theudebert was so uplifted in spirit that he designed to march against Constantinople, and make himself lord of the world (539).