Complex sentence: The first thoroughbred horse farm in Florida was developed in 1943 by Carl G. Rose, who had come to Florida in 1916 from Indiana to oversee construction of the first asphalt road in the state.
Split into simpler sentences: The first thoroughbred horse farm in Florida was developed in 1943 by Carl G. Rose. He had come to Florida in 1916 from Indiana to oversee construction of the first asphalt road in the state.