Almost a thousand years before the birth of Christ, Greeks rowed west on the Adriatic Sea, landed near what is now Brindisi, and ran form the hell of the boot of Italy to the place where Rome stands today. Hundreds of years later, ROmans paved the road from Rome ot Brindisi. They did this to support military and commercial needs. In the current era, roads connected the three capital of the Christian world: Rome Ravenna, and Constantinople. Later Roman paving stones become the material for early Christian churches such as in the Square of Miracles in Pisa. (excerpt)
This itinerary discusses the port cities you will find, if by sea, from London to Rome.