In our own case, a detached prison in a remote location would have been out of the question. Even if it had been provided with a sufficient number of troops, in addition to its clavigers, to fend off the attacks of the autochthons, zoanthrops, and cultellarü who roamed the countryside, not to mention the armed retinues of the petty exultants (who could never be relied upon), it would still have been impossible to provision without the services of an army to escort the supply trains. The Vincula of Thrax is therefore located by necessity within the city — specifically, about halfway up the cliffside on the west bank, and a half league or so from the Capulus.

It is of ancient design, and always appeared to me to have been intended as a prison from the beginning, though there is a legend to the effect that it was originally a tomb, and was only a few hundred years ago enlarged and converted to its new purpose. To an observer on the more commodious east bank, it appears to be a rectangular bartizan jutting from the rock, a bartizan four stories high at the side he sees, whose flat, merloned roof terminates against the cliff. This visible portion of the structure — which many visitors to the city must take for the whole of it — is in fact the smallest and least important part. At the time I was lictor, it held no more than our administrative offices, a barracks for the clavigers, and my own living quarters.

The prisoners were lodged in a slanted shaft bored into the rock. The arrangement used was neither one of individual cells such as we had for our clients in the oubliette at home, nor the common room I had encountered while I was myself confined in the House Absolute. Instead, the prisoners were chained along the walls of the shaft, each with a stout iron collar about his neck, in such a way as to leave a path down the center wide enough that two clavigers could walk it abreast without danger that their keys might be snatched away.