No long time passed before the fame of his invention, spreading not only throughout Flanders but through Italy and many other parts of the world, awakened in all craftsmen a very great desire to know by what method he gave so great a perfection to his works. These craftsmen, seeing his works and not knowing what means he employed, were forced to extol him and to give him immortal praise, and at the same time to envy him with a blameless envy, the rather as he refused for some time to allow himself to be seen at work by anyone, or to reveal his secret to any man. At length, however, having grown old, he imparted it to Roger of Bruges, his pupil, who passed it on to his disciple Ausse[11] and to the others whom we have mentioned in speaking of colouring in oil with regard to painting. But with all this, although merchants did a great business in his pictures and sent them all over the world to Princes and other great persons, to their own great profit, yet the knowledge did not spread beyond Flanders; and although these pictures had a very pungent odour, given to them by the mixture of colours and oils, particularly when they were new, so that it seemed possible for the secret to be found out, yet for many years it was not discovered. But certain Florentines, who traded between Flanders and Naples, sent to King Alfonso I of Naples a panel with many figures painted in oil by Johann, which became very dear to that King both for the beauty of the figures and for the novel invention shown in the colouring; and all the painters in that kingdom flocked together to see it, and it was consummately extolled by all.