Complex sentence: In 654, Derbent was captured by the Arabs, who called it the Gate of Gates ("Bab al-Abwab"), following their invasion of Persia, who transformed it into an important administrative center and introduced Islam to the area.
Split into simpler sentences: In 654, Derbent was captured by the Arabs, who called it the Gate of Gates ("Bab al-Abwab"), following their invasion of Persia. They transformed it into an important administrative center and introduced Islam to the area.