This is third in the love series.
Opera took a big turn around 1828, very close to the death of Beethoven, with an opera called La Muette de Portici which ends with the leading character, a mute woman, throwing herself into an erupting Vesuvius. Opera became violent and politics became significant. Rossini tried to keep in the spirit of things by writing William Tell, but decided he didn't really like this style of opera and retired.
For the first time operas that are not about love became common. Verdi is very political and seems as much interested in political violence, especially at first, as anything. The Verdi screamer soprano parts are from this period in the 1840's. Rigoletto and La Traviata show a softer side.
Russian operas are almost all about politics. Great music is married to subjects of only historical interest.
The successful national movements in Italy and Germany softened the interest in politics, and opera turned back to love as its primary topic with verismo.