 Then Wolfgang fell ill, and it was mid-December before he was on his feet again.Both children were able to appear at the Oude Doelen on 22 January 1766, in a concert which may have included the first public performance of one of Wolfgang's London symphonies, K. 19, and possibly of a new symphony in B flat major K. 22, composed in the Netherlands.Following this concert they spent time in Amsterdam before returning to The Hague early in March.