Complex sentence: His father Appius promises to adopt him to allow his to achieve his goal, which provokes a family feud which is exacerbated when Flavius' young bride-to-be falls in love with Correus.
Split into simpler sentences: His father Appius adopts him to allow his to achieve his goal. This action provokes a family feud which is exacerbated when Flavius' young bride-to-be falls in love with Correus.