The sets of verses begin with three elegiac couplets headed Titulus Bibliothece, probably placed over the door of entrance.

Above or below each niche was fastened to the wall a piece of marble (titulus) on which was cut the name of the owner.

Williams' CVI is possibly correct; the line would then refer to the titulus of the poem in a published text.

To the Latin cross are added the titulus, and a lower diagonal crosspiece which is assumed to be a rest for the feet.