Final answer:
Richard Wagner and Giuseppe Verdi are two renowned Romantic composers known for grand opera, with Verdi's "Aida" being a notable example of such a work.
Step-by-step explanation:
Two romantic composers known for their contributions to grand opera are Richard Wagner and Giuseppe Verdi. Wagner's operas are known for their complex textures, rich harmonies, and elaborate use of leitmotifs, themes associated with particular characters, places, or ideas. Verdi's operas, on the other hand, have been celebrated for their powerful characterizations, melodic invention, and dramatic force. A title of an opera by one of these composers is "Aida", which is one of Verdi's most famous works.