Giuseppe Verdi’s 23rd opera, Un Ballo in maschera, was first performed on Feb. 17, 1859, at the Teatro Apollo in Rome. As a consequence of strict censorship rules and a dicey political situation in France, Verdi and his librettist Antonio Somma had to make many adjustments along the way to finally get the opera produced. More than 150 years later, it’s admired as one of Verdi’s finest scores.