Complex sentence: During that time, he purged the island of counter-revolutionaries, using a guillotine brought from France, and also worked to create a viable post-slavery regime, in which the islands farms and plantations still functioned.
Split into simpler sentences: During that time he purged the island of counter-revolutionaries, using a guillotine brought from France. And he also worked to create a viable post-slavery regime in which the islands farms and plantations still functioned.