Without pausing to trace the concert career of the young virtuoso it must suffice to say, that by the time he was twelve years old, he had become favorably known in every court of southern Europe. His talent had been illustrated in many different ways, and tested by the most severe masters. One of the most celebrated cases of this kind happened at Bologna, where the Philharmonic Academy received him as a member, after his passing the usual severe test, over which the famous master, Padre Martini, presided. The conditions of membership required the candidate to write an elaborate motette in six parts, founded upon a melody assigned from the Roman Antiphonarium, the work to conform to the strictest rules, with double counterpoint and fugue. In consequence of the nervous feeling due to the limit of time allowed, candidates very often failed. Mozart, however, took his paper in the cheerful frame of mind which everywhere distinguished him, and was duly locked up. In less than three-quarters of an hour he rapped at his door and asked to be let out. The authorities sent him word not to be discouraged, but to keep on trying, as he had yet three hours, and might accomplish it. They were greatly astonished on finding that he had already finished, having produced a complete master work, abundantly up to all requirements, the whole written in his peculiarly neat and accurate manner. His compositions had already reached the number of eighty, including a number of symphonies. It was now late in the year 1771, and at Milan Wolfgang set seriously to work upon his opera, which was produced December 26 and repeated to full houses twenty times, the author himself conducting it. This was "_Mitridate, Re di Ponto_." The year following he composed two other operas for Italy, and several symphonies, so that when his new opera of "_Lucio Silla_" was performed in Milan October 24, 1772, the number of his works had reached 135. From 1773 to 1777 Mozart remained at Salzburg, with occasional journeys to Vienna and other cities, always pursuing a life of unflagging industry. The number of his works had increased by the end of this period to upwards of 250, including an immense variety of pieces of chamber music, symphonies, two or three operas, a number of masses, and the like. He was now twenty-one years old, and since the age of fourteen he had been assistant conductor at Salzburg in the service of the prince archbishop, who was a small-souled man, wholly unworthy the service which Mozart rendered him. There is at least a small satisfaction in remembering that the archbishop himself had a distinct impression of the dis-esteem in which he was held by his talented young musical conductor.