Dubris there at anchor "until the ninth hour" (about 3pm) waiting for his supply ships from the second port to come up and meanwhile convening a council of war, he ordered his subordinates to act on their own initiative and then sailed the fleet about seven miles along the coast to an open beach. The Roman fleet in British waters, the "Classis Britannica"'s main purpose was protecting the Gaul-to-Britain routes and supporting the land army in Britannia, not defending the British Isles from invasion. For this reason, its main harbor was in Gesoriacum (Boulogne), not Dover. However, it did have other,
Port of Mainz the centre of Roman life in the area for many centuries. The facilities included a trade port at the 'Dimesser Ort' (in the area of the current port), and a military port (in the area of the current old town), from which the vessels of the Roman river navy patrolled the Rhine. During the gradual Roman retreat from their remaining possessions in front of invading German tribes, some of the naval vessels were abandoned in a section of the port (likely around 407 AD, when the city was sacked for the second time). Their remains rested in the earth and