Complex sentence: After service in the colonies, he married a wealthy Creole, Geneviève Gillot L'Étang, and returning to France purchased the post of lieutenant of the Swiss Guard of the count of Provence.
Split into simpler sentences: After service in the colonies, he married a wealthy Creole, Geneviève Gillot L'Étang. After his return to France, he purchased the post of lieutenant of the Swiss Guard of the count of Provence.