Complex sentence: There he found other returning emigres who were quickly caught up in the political maneuverings, and discovered that Piave was now "Citizen Piave" of the newly-proclaimed Republic of San Marco.
Split into simpler sentences: There he found other returning emigres who were quickly caught up in the political maneuverings. Also, Verdi found that Piave was now "Citizen Piave" of the newly-proclaimed Republic of San Marco.