Task: Question Generation
Input (English): Passage: The Mozarts' first London lodgings were above a barber's shop in Cecil Court, near St Martin-in-the-Fields. 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".Many of the nobility and gentry were leaving town for the summer, but Leopold reckoned that most would return for the king's birthday celebrations on 4 June, and accordingly organised a concert for the 5th. This was deemed a success, and Leopold hastened to arrange for Wolfgang to appear at a benefit concert for a maternity hospital on 29 June, at Ranelagh Pleasure Gardens. Leopold apparently saw this effort to support charitable works as "a way to earn the love of this very special nation". Wolfgang was advertised as "the celebrated and astonishing Master Mozart, a Child of Seven Years of Age..." (he was in fact eight), "justly esteemed the most extraordinary Prodigy, and most amazing Genius, that has appeared in any Age". On 8 July there was a private performance at the Grosvenor Square home of the Earl of Thanet, from which Leopold returned with an inflammation of the throat and other worrying symptoms. "Prepare your heart to hear one of the saddest events", he wrote to Hagenauer in anticipation of his own imminent demise. He was ill for several weeks, and for the sake of his health the family moved from their Cecil Court lodgings to a house in the countryside, at 180 Ebury Street, then considered part of the village of Chelsea.
Output (English): What was the first name of the person who 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?"?