Complex sentence: In 1854, Vance sold the riverfront portion of his property to George L. Haass and Laurent Quintle, who built a dam on the river and constructed a water powered grist mill to process grain and gin cotton for local farmers.
Split into simpler sentences: In 1854, Vance sold the riverfront of his property to George Haass and Laurent Quintle. They built a dam on the river and constructed a water powered grist mill to mill grain for the local farmers.