Conversation so far:
How did the Vienna Boys' Chior get started?
The Vienna Boys' Choir was, for practical purposes, established by a letter from Emperor Maximilian I of the Holy Roman Empire on 30 June 1498.
Who was the singing master of the Vienna Boys' Chior?
The singing master of the Vienna Boys' Choir was Jurij Slatkonja.
Where did the Vienna Boys' Chior sing?
The tradition of the Vienna Boys' Choir singing in weekly Sunday masses at the Imperial Chapel continues today since 1498.

Question: How did it gain popularity?
Self-contained rewrite: How did the Vienna Boys' Chior gain popularity?