Complex sentence: Al-Abbas ibn al-Hasan ibn Ubaidullah ibn al-Abbas was a great celebrity among the Hashemites; he visited Baghdad during the reign of Harun ar-Rashid.
Split into simpler sentences: Al-Abbas ibn al-Hasan ibn Ubaidullah ibn al-Abbas was a great celebrity among the Hashemites. He visited Baghdad during the reign of Harun ar-Rashid.