Complex sentence: In the early 1840s his father had started a business school, the Eastman Commercial College in Rochester, New York, described as one of the first "boomtowns" in the United States, based on rapid industrialization.
Split into simpler sentences: In the early 1840s his father had started a business school, the Eastman Commercial College in Rochester, New York. It was one of the first "boomtowns" in the United States, based on rapid industrialization.