Complex sentence: During the revolutionary wars his father appointed him as aide-de-camp and despatched him to Italy as captain in the being stationed at Rome; after the ban on "émigrés" was lifted in 1800, he returned to France.
Split into simpler sentences: During the revolutionary wars his father appointed him as aide-de-camp and despatched him to Italy as a captain in the being stationed at Rome. After the ban on "émigrés" was lifted in 1800 he returned to France.