X. Thus did the Emperor Justinian at Rhædestus;[82] I now proceed to his works in the Chersonesus. The Chersonesus projects beyond that part of Thrace, for it runs out into the sea and appears as though it proceeded as far as Asia, and was joined on to it. Its shore forms a promontory near the city of Elæus,[83] thus dividing the sea into two parts, while it itself is separated from the rest of the mainland by the water which runs into a recess forming what is called the Black Gulf; the rest of it almost forms an island, from which shape it derives its name, for it is called Chersonesus because it is only prevented by a narrow isthmus from being altogether an island. Across this isthmus the ancients carelessly built a wall which could be scaled with ladders, making it as low and narrow as though they thought they were building a dry stone wall round an out-of-the-way garden. In addition to this they built low and mean works, of the kind called moles, projecting into the sea on either side of the isthmus, and thus fortified the space between the wall and the sea, but in such a manner as not to repel invaders but to invite them to make an attack, so contemptible and easily captured was their fortification. Imagining, however, that they had erected an impassable barrier against the enemy, they did not think it necessary to build any strong place within this wall, for there was no fort or any other place of strength in the Chersonesus, though it extends for a distance of nearly three days’ journey. Quite lately the enemy invaded Thrace, made an attempt upon the passage by the seashore, frightened away its guards, forced their way in as if in sport, and gained the other side of the wall without any difficulty.