In one of his Parallel Lives of the Greeks and Romans,  the 3rd century  A.D. Alexandrian historian PLUTARCH ascribes the building of the first stone bridges across the Tiber River to the ancient Romans, specifically to Numa Pompilio, the fabled second king of the City, a peace-loving lawgiver, high priest, and philosopher comparable to the Greek PYTHAGORAS, for his love of numbers and sense of the divine in nature.

Plutarch explains in his life of Numa that the title used for the high priest -- pontifex -- literally meant bridge builder or keeper, and that this activity  for the Romans was a holy office since they valued the role of the bridge for the City so highly.

I owe this series of pen&ink studies of the evocative old areas on and around the Isola Tiberina in Rome to my classes and sketching sessions with one of my first students in the City. He was a student at St. Stephen's (International) School.