Why is it that the pages of all history glow with the names of illustrious men, while only here and there a lone woman appears who, like the eccentric comet, marks the centuries? -Susan B. Anthony
Historical vocal training is an area which lacks sufficient documentation, which seems to be on account of family training. Vocal training, specifically for women, was not administered in places of higher learning where perhaps documents would've shown a comparison with today's training, including similarities and differences. Also, certain periods stretched when it was deemed illegal for women to perform music and even to be trained in music.
With the invention of opera and the courtly desires to hire women vocalists, a new market of business presented itself to women. They were often bargained for and traided to and fro' different courts, which was technique of keeping peace between courts. Although public opera was looked down upon by high society, it put the vocalist in demand, therefore she could begin demanding her own prices, and she could travel all over Europe by the height of the Baroque period. How she was payed was questionable and certainly went through phases of luxurious gifts to cold hard cash, with an occasional flop here and there.