Complex sentence: This rock relief does not depict a scene of the coronation ceremony of two Sassanid kings, they also depict the demise of the Parthian dynasty, where Artabanus's figure has fallen under the steps of new rulers.
Split into simpler sentences: This rock relief does not depict a scene of the coronation ceremony of two Sassanid kings. However, they depict the demise of the Parthian dynasty, where Artabanus's figure has fallen under the feet of new rulers.