Trio for piano, clarinet or violin and violoncello (B-flat major) op. 11

The B-flat major Trio op. 11, known as the 'Gassenhauer' Trio (Street Ditty Trio), was composed between the end of 1797 and the summer of 1789.

The subject that gave rise to its nickname is taken from the opera L'amor marinaro ossia Il corsaro by Joseph Weigl (1766-1846), one of the most successful Vienna opera composers of his time. The opera was first performed at the Burgtheater on 15 October 1797 and remained in the repertoire until January 1805. Its success was not limited to Vienna alone, and it was even revived at the Kärntnertortheater in 1833. The melody Beethoven used for the third movement was particularly popular and numerous composers (among them Paganini) used it as a subject for variations.

(Maria) Wilhelmine Countess of Thun-Hohenstein, born Countess Uhlfeld (1744-1800), to whom the piece is dedicated, was the grande dame of Vienna's high nobility at that time. The Thun-Hohenstein palace was the city’s social and musical centre. Wilhelmine von Thun had already been a patron of Mozart. The leading artists frequented her salon, among them for example Joseph Haydn. For the young Beethoven she was a key figure in Viennese society and eased his way into aristocratic circles. Many members of the Thun family subscribed to Beethoven's opus 1. It is not known how Beethoven met Wilhelmine von Thun. It is possible that his Bonn patron Count Waldstein gave him an appropriate letter of recommendation before his departure to Vienna (Wilhelmine was a relative of Waldstein). Countess Thun also initiated other connections between Beethoven and his patrons, for two of her daughters were married to Beethoven's patrons: Maria Elisabeth (1764-1806) to Count (later Prince) Andreas Kyrillovich Razumovsky and Maria Christiane (1765-1841) to Prince Karl von Lichnowsky. It is also possible that the Thun-Lichnowsky family helped Beethoven to obtain his second Vienna apartment, the 'Ogylfische Haus', where he lived from spring 1795 onwards.