Complex sentence: This Neo-Byzantine church was built by the architect Henri-Jacques Espérandieu on the foundations of an ancient fort located at the highest natural elevation in Marseille, a 149 m (490 ft) limestone outcrop on the south side of the Old Port of Marseille.
Split into simpler sentences: This Neo-Byzantine church was built by the architect Henri-Jacques Espérandieu on the foundations of an ancient fort. The fort was located at the highest natural elevation in Marseille, a 149 m (490 ft) limestone outcrop on the south side of the Old Port of Marseille.