It is hardly necessary to describe the situation of the town of Ravenna. Its ancient fortress occupied a strong position, resting on the sea towards the east and south, and, with an ample harbour for those days, it could not be blockaded by any army not possessing also a fleet. Lying out of the beaten track, and thus defended by the sea, Ravenna, at a time when Western Europe was convulsed with the commotions dependent upon the extinction of the Western Empire, was contentedly secure under the protection of the yet powerful empire of Constantinople.