Complex sentence: Ficana was located on the left bank of the Tiber downstream from Rome, near present-day Acilia on the highland over Monte Cugno, which in ancient times was steeper and a dominant position on the river.
Split into simpler sentences: Ficana was located on the left bank of the Tiber, downstream from Rome, near present-day Acilia on the highland over Monte Cugno. In ancient times, this provided an advantage as it was steeper and a dominant position on the river.