 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.