Complex sentence: Among the captives was Marie Baron Roussin--widow of Jean Roussin--who in 1731 married Jean-François Benjamin Dumont de Montigny, who more than twenty years later published one of the key histories of the revolt.
Split into simpler sentences: Among the captives was Marie Baron Roussin--widow of Jean Roussin--who in 1731 married Jean-François Benjamin Dumont de Montigny. More than 20 years later, Dumont de Montigny published one of the key histories of the revolt.