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.
Ambos os nenos puideron aparecer no Oude Doelen o 22 de xaneiro de 1766, nun concerto que puido incluír a primeira interpretación pública dunha das sinfonías compostas por Wolfgang en Londres, a KV 19, e posiblemente dunha nova sinfonía en si♭ maior (KV 22), composta nos Países Baixos.