Now Vittigis, in his anger and perplexity, first sent some of his bodyguards to Ravenna with orders to kill all the Roman senators whom he had taken there at the beginning of this war. And some of them, learning of this beforehand, succeeded in making their escape, among them being Vergentinus and Reparatus, the brother of Vigilius, the chief priest of Rome, both of whom betook themselves into Liguria and remained there; but all the rest were destroyed. After this Vittigis, seeing that the enemy were enjoying a large degree of freedom, not only in taking out of the city whatever they wished, but also in bringing in provisions both by land and by sea, decided to seize the harbour, which the Romans call "Portus."This harbour is distant from the city one hundred and twenty-six stades; for Rome lacks only so much of being on the sea; and it is situated where the Tiber River has its mouth.[131] Now as the Tiber flows down from Rome, and reaches a point rather near the sea, about fifteen stades from it, the stream divides into two parts and makes there the Sacred Island, as it is called. As the river flows on the island becomes wider, so that the measure of its breadth corresponds to its length, for the two streams have between them a distance of fifteen stades; and the Tiber remains navigable on both sides. Now the portion of the river on the right empties into the harbour, and beyond the mouth the Romans in ancient times built on the shore a city,[132] which is surrounded by an exceedingly strong wall; and it is called, like the harbour, "Portus." But on the left at the point where the other part of the Tiber empties into the sea is situated the city of Ostia, lying beyond the place where the river-bank ends, a place of great consequence in olden times, but now entirely without walls. Moreover, the Romans at the very beginning made a road leading from Portus to Rome, which was smooth and presented no difficulty of any kind. And many barges are always anchored in the harbour ready for service, and no small number of oxen stand in readiness close by. Now when the merchants reach the harbour with their ships, they unload their cargoes and place them in the barges, and sail by way of the Tiber to Rome; but they do not use sails or oars at all, for the boats cannot be propelled in the stream by any wind since the river winds about exceedingly and does not follow a straight course, nor can oars be employed, either, since the force of the current is always against them. Instead of using such means, therefore, they fasten ropes from the barges to the necks of oxen, and so draw them just like waggons up to Rome. But on the other side of the river, as one goes from the city of Ostia to Rome, the road is shut in by woods and in general lies neglected, and is not even near the bank of the Tiber, since there is no towing of barges on that road.So the Goths, finding the city at the harbour unguarded, captured it at the first onset and slew many of the Romans who lived there, and so took possession of the harbour as well as the city. And they established a thousand of their number there as guards, while the remainder returned to the camps. In consequence of this move it was impossible for the besieged to bring in the goods which came by sea, except by way of Ostia, a route which naturally involved great labour and danger besides. For the Roman ships were not even able to put in there any longer, but they anchored at Anthium,[133] a day's journey distant from Ostia. And they found great difficulty in carrying the cargoes thence to Rome, the reason for this being the scarcity of men. For Belisarius, fearing for the fortifications of Rome, had been unable to strengthen the harbour with any garrison at all, though I think that if even three hundred men had been on guard there, the barbarians would never have made an attempt on the place, which is exceedingly strong.