The Imperial Chapel Choir was founded in Vienna in 1498 and performed exclusively for the court.  Composers that worked with the choir included Musicians like Heinrich Isaac, Paul Hofhaimer, Heinrich Ignaz Franz Biber, Johann Joseph Fux, Wolfgang Amadeus Mozart, Antonio Caldara, Antonio Salieri and Anton Bruckner.  Schubert was a chorister.  After the dissolution of the Hapburg Empire in 1918, it became a touring choir: The Vienna Boys Choir.  

Below is an account from 1612 of the choir boy’s conditions:

Since our “Kapellmeister” or others, are to give board and lodging to our Chapel Boy Singers, he shall receive for each boy, for food, for lodging, salt, light, laundry, mending expenses, barber, bath money, and similar items, the monthly sum of 4 florins 50 kreuzer, but the boys must, as is seemly, have as much food and drink as they need. On meat days three, and on fish days four good courses, and during the week three times roast, well kept and clean, and soup and meat should not be given for two, but for one course only, and meat and cabbage too, are to be counted as one course.

Then the drinking of wine shall be regulated: namely, each boy is to have with his meal one and a half pitcher of wine, but let it be such a wine, that will not make the boy sick, and for this he, the Kapellmeister is supposed to be responsible.

And also, the boys habitually should have a soup each morning, and later in the day some bread, which shall be served to them if they want it. Added to this, there is to be allowed one thaler monthly, making 14 Gulden a year, for six new shirts (40 kr. each) and for three pairs of pants (woolen in the winter, and leather in the summer); also two fustian jerkins (doublets), woolen in winter, the one for summer, however, without wool, together with price of making them at 6 florins each, and also a pair of shoes at 15 kr. for every month should be given to them. Paper, pen and ink, and other articles needed for writing should also be given, and 6 kr. a month be allowed for this expense.

Vienna, State Archives: The Imperial Court Music Chapel in 1543-1612.

Cited in: Nettle, Paul (1948) The Book of Musical Documents.  New York: Philosophical Library, pp.59-60.