Under the influence of testicular secretion, the male vocal cords increase in length by 67% in adult men compared with prepubertal boys, whereas in the female the increase is only 24%. This greater length and an increase in vocal cord mass is responsible for the lowering of pitch of the male voice during puberty. From the late 16th century, castration was carried out in Italy to preserve the unbroken male voice into adult life, but the high pitch was accompanied by fully grown resonating chambers and a large thoracic capacity, giving rise to the unique voice of the castrato. The initial stimulus for the production of castrati came from the Sistine Chapel in Rome, to provide singers for the complex church music of the time. The second reason was the coming of opera to Italy at the beginning of the 17th century. Boys were castrated between the ages of 7 and 9 years, and underwent a long period of voice training. A small number became international opera stars, of whom the most famous was Farinelli, whose voice ranged over three octaves. By the end of the 18th century, fashions in opera had changed so that the castrati declined except in the Vatican, where the Sistine Chapel continued to employ castrati until 1903. The last of the castrati was Alessandro Moreschi, who died in 1924 and made gramophone recordings that provide the only direct evidence of a castrato's singing voice.