In the reign of Trajan there lived a knight named Placidus, who was commander-in-chief of the emperor's armies. He was very merciful, but a worshipper of idols. His wife too was an idolater. They had two sons, brought up in all magnificence, and from the kindness and goodness of their hearts, they deserved a revelation of the way of truth.
As he was one day following the chase, Placidus discovered a herd of deer, amongst which was one remarkable for size and beauty. Separating itself from the rest, it plunged into the thickest part of the brake. While the hunters, therefore, occupied themselves with the remainder of the herd, Placidus swiftly followed this deer's track. The stag scaled a lofty precipice, and Placidus, approaching as near as he could, considered how it might be followed yet. But as he regarded it with fixed attention, there appeared upon the centre of the brow, the form of the cross, which glittered with more splendour than the noonday sun. Upon this cross an image of Jesus Christ was suspended; and the stag thus addressed the hunter: "Why dost thou persecute me, Placidus? For thy sake have I assumed the shape of this animal. I am Christ, whom thou ignorantly worshippest. Thine alms have gone up before me, and therefore I come; but as thou hast hunted this stag, so will I hunt thee."
Some indeed assert that the image, hanging between the deer's antlers, said these things. However that may be, Placidus, filled with terror, fell from his horse; and in about an hour, returning to himself, arose from the earth and said, "Declare what thou wouldst have, that I may believe in thee."
"I am Christ, O Placidus! I created heaven and earth; I caused the light to arise, and divided it from the darkness. I appointed days, and seasons, and years. I formed man out of the dust of the earth; and I became incarnate for the salvation of mankind. I was crucified, and buried; and on the third day I rose again."
When Placidus understood these sublime truths, he fell again upon the earth, and exclaimed: "I believe, O Lord, that thou hast done all this; and that thou art He who bringest back the wanderer."
The Lord answered: "If thou believest this, go into the city and be baptized."
"Wouldst thou, O Lord, that I tell what has befallen me to my wife and children, that they also may believe?"
"Do so; tell them, that they also may be cleansed from their iniquities. And on the morrow return hither, where I will appear again, and show you of the future."
Placidus, therefore, went to his own home, and told all that had passed to his wife. But she too had had a revelation; and in like manner had been enjoined to believe in Christ, together with her children. So they hastened to the city of Rome, where they were entertained and baptized with great joy. Placidus was called Eustacius, and his wife, Theosbyta; the two sons, Theosbytus and Agapetus.
In the morning, Eustacius, according to custom, went out to hunt, and coming with his attendants near the place, he dispersed them, as if for the purpose of discovering the prey. Immediately the vision of yesterday reappeared, and prostrating himself, he said, "I implore thee, O Lord, to manifest thyself according to thy word."