Cestria vulgo Chester, Angliae Civitas.

A stunning town plan of the northern city of Chester, with heraldic shields, Royal and civic coats of arms, explanation table, dividers and Elizabethan figures in the foreground.
The schematic bird's-eye view shows the city from the south, ringed by a nearly square-shaped city wall. On top of the man-made knoll in the left foreground lies Chester Castle (20), a defensive fortification against Celtic assaults, which was erected following the Norman Conquest in 1066 to secure the nearby bridge (23) over the River Dee.

Chester was founded two millennia ago as Castra Devana, serving a Roman Legion that was posted there to ward off the Celtic Welsh as an important harbour and defensive position. Following the withdrawal of the Romans, the Anglo-Saxons extended the walls in order to protect the city against incursions by the Danes.
Fortified further during Norman times, Chester was intermittently the largest inland harbour in England, whose transhipment activities brought prosperity to the city.

CARTOUCHE BOTTOM READS: The River Dee divides England and Wales. It has its source in the north of Wales and flows into the sea called Tegaeus, in whose waters lives a specific type of fish that never swims up river, just as the salmon that swarm the river never venture into the aforesaid sea.

Reference: Taschen B & H p. 205