In her new book “Changing the Score: Arias, Prima Donnas, and the Authority of Per­for­mance” (Oxford Uni­ver­sity Press, the AMS Series in Music), North­eastern Uni­ver­sity assis­tant music pro­fessor Hilary Poriss reveals some of the back­stage drama in Italian oper­atic his­tory that set the tone for some of the world’s most famous scores.

In their heyday, 19th-​​century Italian opera per­formers were the ‘Angelina Jolies’ and ‘Brad Pitts’ of their time, according to Poriss. Their celebrity status gave them the power to make or break the careers of some of the most famous com­posers of the time—legends like Rossini, and Donizetti—and these oper­atic stars flaunted their status by making changes to operas as they saw fit.

Singers had a lot of power in the 19th cen­tury. They were the ones audi­ences came to see,” Poriss says. “Opera was the main form of enter­tain­ment in Italy at the time, and so singers were paid more than composers—a tra­di­tion that goes back to the 17th cen­tury. The­ater man­agers and com­posers knew that the audi­ence came to hear their favorite singer, and not the new opera.” Just like today’s audi­ences are drawn to see their favorite movie stars on-​​screen.

Hol­ly­wood celebri­ties, how­ever, rarely get the artistic license granted to opera singers of that time, who rou­tinely over­looked com­posers’ scores and inserted their own favorite arias into the performances.

In the famed “lesson scene” in Rossini’s “The Barber of Seville,” for example, the composer’s work was rarely per­formed. Instead, a per­former would intro­duce another aria, often by another com­poser, that they felt fit the overall opera, explains Poriss. “This is some­thing that would never happen today. But at the time, from about 1825 to 1850, we really saw a growth in Prima Donnas, and com­posers were utterly reliant on them.”

A vio­linist since she was four, Poriss was drawn to music his­tory and the opera during her under­grad­uate years at Bates Col­lege, where she “dis­cov­ered the whole world of music his­tory.” She also found that she felt more com­fort­able in a class­room set­ting teaching than she ever had on stage playing the violin.

After earning her under­grad­uate degree, she studied with the renowned music pro­fessor Philip Gos­sett at the Uni­ver­sity of Chicago, earning her master’s and later her doc­torate in music his­tory. Prior to coming to North­eastern in 2006, she won the pres­ti­gious Rome Prize from the Amer­ican Academy in Rome to travel to Italy and com­plete her book.

Her work is lauded by Susan Ruther­ford, author of “The Prima Donna and Opera, 1815–1930,” for its “lively prose and fresh per­spec­tives of a little explored area of oper­atic per­for­mance prac­tice.” Poriss’s first book, which is part of the Amer­ican Musi­co­log­ical Society Series on Music, also gar­nered praise from Mark Everist, also an author of two books on music his­tory, and who said of her work: “Hilary Poriss invites us into a world where so many musical cer­tain­ties seem to vanish.”