Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter LX

Chapter LX.—He also erected his own Sepulchral Monument in this Church.

All these edifices the emperor consecrated with the desire of perpetuating the memory of the apostles of our Saviour. He had, however, another object in erecting this building: an object at first unknown, but which afterwards became evident to all. He had in fact made choice of this spot in the prospect of his own death, anticipating with extraordinary fervor of faith that his body would share their title with the apostles themselves, and that he should thus even after death become the subject, with them, of the devotions which should be performed to their honor in this place. He accordingly caused twelve coffins to be set up in this church, like sacred pillars in honor and memory of the apostolic number, in the center of which his own was placed, having six of theirs on either side of it. Thus, as I said, he had provided with prudent foresight an honorable resting-place for his body after death, and, having long before secretly formed this resolution, he now consecrated this church to the apostles, believing that this tribute to their memory would be of no small advantage to his own soul. Nor did God disappoint him of that which he so ardently expected and desired. For after he had completed the first services of the feast of Easter, and had passed this sacred day of our Lord in a manner which made it an occasion of joy and gladness to himself and to all; the God through whose aid he performed all these acts, and whose zealous servant he continued to be even to the end of life, was pleased at a happy time to translate him to a better life.