which goes beyond the routine methods of his [grown-up] contemporaries". These are Wolfgang's first orchestral writings, although Zaslaw hypothesises a theoretical "Symphony No. 0" from sketches in Wolfgang's musical notebook. Three lost symphonies, identified in the Köchel catalogue of Mozart's works only by their incipits (first few bars of music), may also have originated from the London period. Other works composed by Wolfgang in London include several instrumental sonatas, the jewel of which, according to Hildesheimer, is the C major sonata for piano, four hands, K. 19d. A set of violin sonatas, with extra flute and cello parts, was dedicated to Queen Charlotte at her request, and presented to her with an appropriate inscription in January 1765. Wolfgang also wrote his first vocal works, the motet "God is our Refuge", K. 20, and the tenor aria Va, dal furor portata, K. 21. At the end of September, with Leopold's recovery, the family moved back to central London, to lodgings in Thrift Street (later 20 Frith Street), Soho. These lodgings were located conveniently close to several concert rooms, and to the residences of both J. C. Bach and Carl Friedrich Abel. Bach, a son of Johann Sebastian Bach, soon became a family friend; Nannerl later recalled Bach and the eight-year-old Wolfgang playing a sonata together, taking turns to play a few bars individually, and that "anyone not watching would have thought it was played by one person alone". There is no record that the Mozarts met Abel, but Wolfgang knew his symphonies, perhaps through the medium of the annual Bach-Abel concert series, and was much influenced by them. On 25 October, at King George's invitation, the children played at the celebrations marking the fourth anniversary of the king's accession. Their next public appearance was a concert on 21 February 1765, before a moderate audience—the date clashed with a Bach-Abel concert. Only one more London concert was given, on 13 May at Hickford's Long Room, but between April and June members of the public could go to the Mozarts' lodgings where, for a five shilling fee, Wolfgang would perform his musical party pieces. During June both the "young Prodigies" performed daily at the Swan and Harp Tavern in Cornhill, the charge this time being a mere two shillings and sixpence. These were, as Sadie puts it, "Leopold's last, desperate effort to extract guineas from the English public". Hildesheimer likens this part of