Complex sentence: Saracen was a term used by the ancient Romans to refer to the Arabs then the term was expanded by Europeans in the Middle Ages, to include all who professed the religion of Islam, not necessarily Arabs.
Split into simpler sentences: Saracen was a term used by the ancient Romans to refer to the Arabs. The term was then expanded by Europeans in the Middle Ages, to include all who professed the religion of Islam, not necessarily Arabs.