EDITORUM PATROLOGIÆ PRÆFATIO
A Instituted from childhood in sacred and secular letters, Constantine Porphyrogenitus, son and pupil of Leo the Wise, issued more volumes than his father, in which his supreme erudition and immense love of letters shine forth wondrously. However, the greater part of his writings concerns secular subjects; a smaller part treats matters of a moral or sacred order. The *Catanuctia* odes, which he composed for the use of the Church, we have already edited with the liturgical writings of his father, in volume CVII of the *Patrologia*, page 299. The homily on the translation of the relics of Saint John Chrysostom, which Allatius asserts exists in *De Symeonum scriptis*, p. 111, we do not have at hand. We do, however, have his homily *On the Translation of the Image of Edessa*, edited by Combefis in *Manipulus rerum Constantinopolitanarum*. Some have doubted that this was written by Constantine Porphyrogenitus, considering that it should be attributed to one of Constantine’s successors. But wrongly. For it is certain from Constantinopolitan history that the image of Edessa was translated to Constantinople in the year of the Lord 944, and the homily recited on this occasion was composed by the Emperor of Constantinople. Furthermore, in the year 944, no emperor reigned in Constantinople except Constantine; he, therefore, and not another, must be considered the author of this homily. B The *Novellae Constitutiones* of Constantine are almost all of a sacred or ecclesiastical nature; and accordingly they had to be repeated here. The first is called by the Greeks the *Tome of Union*, because it put an end to the schism that had arisen in the Eastern clergy on account of the fourth marriage of Leo the Wise. In the work *On the Ceremonies of the Byzantine Court*, book 1, chapter 36, are read the "Observances in the procession of the Union of the Church," or when the *Tome of Union* of the Church is read; from which it may be gathered that an anniversary feast of that union was once celebrated in Constantinople. This work, *On the Ceremonies of the Byzantine Court*, serves greatly to elucidate Eastern ecclesiastical history and the civil state of the Church in the East. For it is composed of ancient and new documents, diligently collected, by which the rights, duties, and functions of both powers are described. From it, it appears that the Patriarch of Constantinople occupied the first place in the entire empire after the emperor; and he very often administered civil affairs, no differently than the emperor presumed to moderate ecclesiastical affairs. C In many things the emperor, as a most obedient son of the Church, submitted himself to the authority of the patriarch; but likewise the Patriarch of Constantinople was accustomed to conduct himself as a most devoted subject of the emperor. In public court ceremonies, however, they seemed to be of almost equal authority and dignity. Nevertheless, the Roman Pontiff, in that age, namely after the Photian schism, was treated as the first patriarch and head of the whole Church. He alone was called by the emperor his "Spiritual Father," by which name no patriarch besides him was addressed, as can be seen in the formulas of writing to the patriarchs which the Emperors of Constantinople used, and which Constantine Porphyrogenitus collected in the work *On the Ceremonies of the Byzantine Court*, book II, chapter 48. In the same place, not only the ceremonies to be employed in the future are described, but also those which had been employed at some time when foreign princes visited the city of Constantinople. Thus, for example, we read there with what rites the most famous Princess Olga of Russia was received by the emperor, who came to Constantinople at the beginning of the tenth century, and shortly after the conversion of the Russians prepared the way for the Christian faith. D By the order of Constantine Porphyrogenitus, there was also composed a *Compendium of Civil and Ecclesiastical Laws*, from which the rights of the Church and its fortunes in the Eastern Empire are known. Besides the *Life* of his father Leo and his grandfather Basil the Macedonian, Constantine wrote a *History of Ancient Kingdoms*, or rather he collected *Historical Excerpts* of ancient writers, a specimen of which is exhibited by the Most Eminent Cardinal A. Mai in *Scriptorum veterum nova collectio*, vol. II, page 1, and in the preface, which have lately supplied many fragments of lost writers