Complex sentence: He wrote an important book on the history of medicine, and his works in pharmacology were widely quoted during the 10th and 11th century Muslim Spain, and said to have been studied by Albertus Magnus.
Split into simpler sentences: He wrote an important book on the history of medicine, and his works in pharmacology were widely quoted during the 10th and 11th century Muslim Spain. His works are said to have been studied by Albertus Magnus.