 Letters of introduction from Paris proved effective; on 27 April 1764, four days after their arrival, the children were playing before King George III and his 19-year-old German queen, Charlotte Sophia.A second royal engagement was fixed for 19 May, at which Wolfgang was asked by the king to play pieces by Handel, Johann Christian Bach and Carl Friedrich Abel.He was allowed to accompany the queen as she sang an aria, and he later improvised on the bass part of a Handel aria from which, according to Leopold, he produced "the most beautiful melody in such a manner that everyone was astonished".