See p. 4 of Le quattro stagioni (libretto for the 1811 Bologna performance published by Ramponi)
comune.bologna.it
badigit.comune.bologna.it
Biblioteca comunale dell'Archiginnasio di Bologna. Letter from Elisabetta Manfredini to the audience of the Teatro Contavalli. Benefit performances, where an opera's singer, conductor or composer received all the box-office takings for a particular performance in addition to their salary, were a common practice in the 18th and 19th century operatic world. For more, see Price et al. (1995) Chapter 3, Part II, "Recruitment and Salaries".
