Complex sentence: Pensive was brought to the U.S. still forming in his mother's womb by A.B. Hancock who then sold the mare to the owner of Calumet Farm, Warren Wright, who'd inherited it from his father, William Monroe Wright president of the Calumet Baking Powder Company.
Split into simpler sentences: Pensive was brought to the U.S. still forming in his mother's womb by A.B. Hancock who then sold the mare to the owner of Calumet Farm, Warren Wright. Warren had inherited Calumet from his father, William Monroe Wright, president of the Calumet Baking Powder Company.