When listening to an opera in Italian which I mistook for Spanish at first, I started wondering why most operas, symphonies and so on that I know from the 18th and 19th centuries were written by composers from or working in Italy, the Holy Roman Empire, France and Russia, but few from Spain or Portugal. Could it have something to do with the Spanish Empire's often discussed economic decline and political chaos in the 18th/19th centuries (possibly in connection with the Leyenda negra)? As composers were often sponsored by aristocrats, did Spain's long royal and Catholic tradition(s) mean a lack of sponsorship compared to more Protestant regions, like i.e. the Germanic duchies? Or maybe I'm just missing out on a lot of great Hispanic Classical Music (which of course existed). Would be grateful for any input and ideas.
Some of a yes and no on this! There are some very nice Spanish operas from the Baroque, Classical and Romantic period, the first operas performed in the New World were in Spanish actually, but you're right that Italian was the language of choice for opera. This is to do more with the people making the opera than those consuming it, that is to say, most of the singers were Italian, and it was not customary until mmm maybe the 1940s-50s or so for opera singers to be multilingual and willing to sing every language. Opera singers were accustomed to singing in one language only, and in that period all the best opera singers were Italian (which is a longer story) and so opera was in Italian. There were some (no doubt very weird to sit through) examples of mixed-cast operas in London in the 18th century, where the native cast all sang in English and the Italian singers just dogged on in Italian! And keep in mind Spain controlled large chunks of Italy for large chunks of time, so it wasn't a big deal for them to consume Italian culture.
Some of it is also dependent on temperament of the Spanish royals as well. The Spanish courts in the first half of the 1700s were great fans of music and would import many Italian composers and singers to make opera for them. Domenico Scarlatti and Farinelli working in the Spanish court in the 1730s-1750s is the most well known (and productive) musical duo of Italian-Spaniards. Farinelli was put in charge of all the operas for the Spanish court around 1740, and he did them all in Italian, as was customary at the time, using Italian librettists, but he did work with some local Spanish composers I believe. But when Charles III took the throne, he was not into music and Farinelli (and others) were sent home.
Portugal is basically the same story, they imported singers, but they got a setback on everything with the earthquake of 1755. They'd just built a new beautiful state opera house spring of that year, and it was completely destroyed in the earthquake. They'd actually imported lots of hot Italian opera singers to inaugurate it, including my username, and they all had to flee the ruined city after the earthquake. Not sure if they got paid! And Lisbon didn't get a new opera house until 1793. So that's why Portuguese opera is even less common.
The basic story though, is that opera was pretty much exclusively an Italian import for many countries until the mid-classical period or so, when Italian opera singers started to lose their absolute dominance of the field.
Edit: some suggested reading:
For Italian singers and composers in the European musical economy, try Music in European Capitals: The Galant Style, 1720-1780 by Daniel Heartz (2003), or the incomparable Singers of Italian Opera: The History of a Profession by John Rosselli (1992). For Domenico Scarlatti's time working in Spain, try Alessandro and Domenico Scarlatti: Two Lives in One by Roberto Pagano (2006), the back half of the book. I also have some neat stuff on Farinelli's pianos/harpsichords he designed and commissioned in Spain, but that's getting into the realm of exceedingly specialized literature. :)
Well, Italy really led the European music world in the Baroque, with developing forms ( like concertos) and terms for speed of playing and style, which are still used ( adagio, presto, smorzando, etc) and also exporting teachers and composers- Scarlatti might have lived in Spain, but he was Italian. Germany/Austria become more dominant in the Classical period and into the 19th century, in both developing louder instruments and with composers like Beethoven writing for big orchestras and piano- and he and composers like Hayden did benefit from having patrons. Protestant or Catholic does not seem to have mattered; having a private orchestra was just something an important family like the Esterhazy's would often do.
The collapse of Spain as a world power must have helped take it down as a major musical influence. It continued to have music ( zarzuela for example... if you search under zarzuela on You Tube you'll see what they'd do for opera, and of course composers like Fernando Sor developed impressive guitar music ) But it definitely lost out to Italy and Germany, for exporting culture.