In 1514 the prince of Italian painters and the noblest of German artists exchanged pleasant civilities by correspondence, accompanied by specimens of their labors. Dürer sent to Raphael his own portrait, which was afterwards inherited and dearly prized by Giulio Romano. Raphael returned several of his own studies and drawings, one of which, showing two naked men drawn in red crayon, is now preserved in the Albertina at Vienna. It still bears Dürer's inscription: "Raphael of Urbino, who is so highly esteemed by the Pope, has drawn this study from the nude, and has sent it to Albert Dürer at Nuremberg, in order to show him his hand." The invention of the art of etching has been generally attributed to Dürer, though it now seems that he merely improved and perfected the process. There are but few etchings in existence which can certainly be ascribed to him; and the chief of these, an "Ecce Homo" and "Christ in the Garden," date from 1515. The iron plate of the latter was found two centuries later, in a blacksmith's shop, where it was about to be made into horse-shoes. A third etching represents a frightfully homely woman being carried off by a man on a unicorn, a wild and incomprehensible composition, calculated to awaken an uncomfortable impression in the beholder. Some of the etchings were on iron, and others on pewter; but none were on copper, which was afterwards universally used. The corrosive nitrous acid acted inefficiently on the metals which he employed, and so his etchings fall short of excellence. In 1514 Jorg Vierling uttered disgraceful libels and threats against Dürer, and finally attacked him in the street. He was imprisoned by the authorities; but the kind-hearted artist interceded for him, and he was released, after being bound over to keep the peace. In the same year Dürer wrote to Herr Kress to see if the laureate Stabius had done any thing about his delayed pension; saying also, "But if Herr Stabius has done nothing in my matter, or my desire was too difficult for him to attain, then I pray of you to be my favorable lord to his Majesty.... Point out to his Majesty that I have served his Majesty for three years, that I have suffered loss myself from doing so, and that if I had not used my utmost diligence his ornamental work would never have been finished in such a manner; therefore I pray his Majesty to reward me with the 100 guilders." In September an imperial decree was issued, giving Dürer his promised pension of $200 a year out of the tax due from Nuremberg to the Emperor. This annuity was paid to the artist until his death, with one short intermission.