Saint Dionysius the Areopagite, in the book On the Divine Names, chapter 3, at the end, writes as follows:
“Since even among our own hierarchs, inspired by God, when we also, as you know, and you yourself, and many of our sacred brethren had come together to behold the body which gave the principle of life and received God, there was also present James, the brother of God, and Peter, who was the supreme and most ancient summit of the theologians; it seemed good that after that spectacle all the hierarchs should sing a hymn,” and so forth.
The Greek Fathers received these as true words of the Areopagite speaking about himself, with great agreement. From there a most ancient tradition flowed into the Church: that at the death of the Virgin Mother of God all the Apostles, and blessed Dionysius and Timothy, were present. At the time of the Synod of Chalcedon, when Marcian and Pulcheria asked for it, Julian, Bishop of Jerusalem, testified to this in these words:
“Then there were present with the Apostles the most holy Timothy, Apostle and first Bishop of the Ephesians, and Dionysius the Areopagite; just as this great Dionysius himself testifies in those things which he wrote to the lord Apostle Timothy concerning blessed Hierotheus, who himself also was then present, saying as follows: ‘Since,’ and so forth.”
For he then adds the cited words of Dionysius. Euthymius the historian, book 3, chapter 40, cited by blessed John Damascene in the oration On the Dormition of the Mother of God, brings forward this testimony of blessed Julian. Nicephorus Callistus reports the same thing in book 15 of his History, chapter 14. Epiphanius the Presbyter also, in the oration On the Dormition of the Mother of God, Symeon Metaphrastes, Michael Syncellus in praise of Dionysius, Maximus in the scholia on Dionysius, Glycas in book 1 of the Annals, and other Greeks in a certain hymn concerning the Mother of God embrace the same authority and the same words as belonging to the Areopagite.
Read Petrus Canisius, book 5 of the Marian work, chapter 3, and Cardinal Baronius, volume 1 of the Annals, at the year of Christ 48, number 8, where he learnedly shows that this is the true opinion of Dionysius.