Vasari then proceeds to tell us of Jan's great success, of the "blameless envy" of all other artists in Flanders and abroad, from whom he would jealously guard his secret, until, in his old age, he imparted it to "his disciple Ruggieri da Bruggia," a name which surely can hide no other personality than Rogier van der Weyden's. Of Hubert never a mention, save a short reference in the last volume, in the chapter on "Divers Flemish Artists." As in most of Vasari's anecdotes, there is probably a foundation of truth to the elaborate network of fiction. The incident explained by him at great length may have occurred, but its hero can only have been Hubert, and not Jan, who was then a mere youth working in his brother's _bottega_, and may have assisted Hubert in his experiments. Though it has since been doubted that Hubert or Jan van Eyck actually invented oil-painting, no evidence has yet been discovered to prove they were not the first to employ oil {23} as a medium in putting colour on the prepared panel. It is true that oil as a protective varnish was frequently used during the fourteenth century, and it is probable that some kind of oil-colour was employed in the colouring of statuary and in the painting of banners at an early period. For this reason the statement that Hubert and Jan van Eyck "discovered painting in oils" has been disputed, and generally accepted as inaccurate, but the question is one rather of terminology than of the technical point. As the term "oil-painting" is generally accepted to-day, it is fairer to credit these brothers with the invention, than to speak of their achievement as an improvement in oil-painting, for hitherto the medium in common use had been a preparation of gum and white of eggs. And as there is neither definite proof nor any good evidence that oil had ever been used as a _medium to mix the colours_ for panel-painting before Hubert and Jan made their experiments, we surely have an easy distinction to draw. The brothers Van Eyck were the first successfully to mix the oil with the colours for painting, and this process is what we now understand as "painting in oils." The use of {24} oils as a protective or varnish does not enter into the painting, since such had only been used on the completion of the work. For the rest, the brothers either acted more generously than Vasari would have it, or they did not altogether succeed in guarding their precious secret, for their method appears to have been fairly generally practised at Ghent about 1420. We find, for instance, that in 1419 the "free painters," Willem van Appoele and Johannes Maertens, received a commission to paint some pictures for the town hall of Ghent in "good oil-colours." It is also certain that Rogier van der Weyden--Vasari's Ruggieri da Bruggia--never was a pupil of either Jan or Hubert van Eyck. {25} THE ART OF THE VAN EYCKS