At this time he was chiefly known as a virtuoso, and his first appearance in public was March 29, 1795, in a concert at the Burgtheatre for the benefit of the widows of the Society of Musicians. An oratorio by Cartellieri was given, and Beethoven played his pianoforte concerto in C major, which was published six years after as Op. 15. At rehearsal there was a difference of half a tone between the pitch of the pianoforte and that of the orchestral instruments, and the composer played the concerto in C sharp major. In the same year he made a contract with Artaria for the publication of his first three pianoforte trios. Two hundred and forty-two copies were subscribed for, and the composer netted about $400, a respectable sum at that time, especially for the early works of a young man. In 1796 Beethoven went to Nuremberg, where he met his Bonn friends, the Breuning brothers, and for some reason not clearly known, they were arrested at Linz by the police, but were quickly released. On his return to Vienna he busied himself in overseeing the publication of sonatas (Op. 2), minuets and variations. His brothers were in the city. Johann, "tall, black, handsome, a complete dandy," found a place in an apothecary shop. Caspar, "small, red-haired, ugly," gave music lessons. In February Beethoven was in Prague and in Berlin, the only occasion on which he visited "the Athens of the Spree." Frederick William II. was gracious to him, heard him play, and gave him a snuff-box filled with gold pieces; "not an ordinary box," as Beethoven proudly said when he showed it, "but such a one as they give to ambassadors." Beethoven also met Prince Louis Ferdinand and complimented him by saying, "you play like an artist, not like a prince." He jeered at Himmel's improvisation, and Himmel in turn persuaded him that a lantern had been invented for the benefit of the blind. He saw Fasch and Zelter. When he returned to Vienna the talk was of Napoleon conquering in Italy.