Teatro alla Scala
The Doctor as Canio/Pagliaccio from Pagliacci
The Teatro alla Scala was one of the most famous opera houses on Earth, located in the city of Milan.
For his first performance before the Qomar in 2376, The Doctor chose to reproduce the backdrop from a production of Pagliacci in the Teatro alla Scala. (VOY: "Virtuoso")
The Teatro alla Scala was built by Giuseppe Piermarini between 1776 and 1778. (Star Trek Encyclopedia, 4th ed., vol. 2, p. 377)