Complex sentence: The wrought iron grill of the entrance is from the late 17th century; of the original line of walls that surrounded the abbey, today only two small sections are visibile near the entrance tower, while no trace remains of the ditch.
Split into simpler sentences: The wrought iron grill of the entrance is from the late 17th century. Nearby are the only remains of the original line of walls that surrounded the abbey; no traces remain of the ditch.