Map of Bath
An interactive map of Bath
The western border of early Roman Briton made a beeline from Lincoln to Exeter, never deviating more than 6 miles from its centerline (those Romans). It later became a road, known as the Fosse Way after the original fossa, or defensive ditch, it followed.
The road crossed the River Avon at the spa town of Aquae Sulis (modern-day Bath), but along much of its route Roman military encampments sprang up many Roman military encampments, known as castrum. This devolved into the Old English cæster, then to the modern "-cester" at the end of many a British city or town (Leicester, Cirencester, Dorcester, etc.).
Want more? The Fosse Way was the main paved road, or "strata" through the region. This became the Old English strǣt, which became not only the word "street," but along the etymyological way gave us "strat" and "stret" variants, like Stratford-upon-Avon, or my favorite: Strettford-on-Fosse.